今天看啥
热点:

Android开发,


 

目录截图:

  

1、activity_main.xml

 主界面效果:

      

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:scrollbars="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
   <LinearLayout
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:id="@+id/activity_main"
       android:orientation="vertical"
       >
      <TextView
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:id="@+id/title"
          android:textSize="25dp"
          />
      <Button
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:text="Insert()方法案例"
          android:onClick="test_1"
          />
      <LinearLayout
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:orientation="horizontal"
          >
         <Button
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="添加学生"
             android:onClick="addStu"
             android:layout_weight="1"
             />
         <Button
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="测试监听"
             android:onClick="test"
             android:layout_weight="1"
             />
         <Button
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="学生信息列表"
             android:layout_weight="1"
             android:onClick="loadStuList"
             />
      </LinearLayout>
      <ListView
          android:layout_width="match_parent"
          android:layout_height="350dp"
          android:id="@+id/stuListView"
          android:divider="@android:color/holo_orange_light"
          android:dividerHeight="2dp"
          />
      <Button
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:text="安全退出"
          android:onClick="safeExit"
          />
   </LinearLayout>
</ScrollView>

2、MainActivity.java

package com.nf.android_sqlite2;

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;
import android.widget.Toast;
import com.nf.dao.StuDao;
import com.nf.utils.MyApplication;

public class MainActivity extends Activity {
    private TextView title;
    private ListView stuListView;
   //适配器
private SimpleCursorAdapter adapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); MyApplication.getInstance().addActivity(this); title = (TextView)findViewById(R.id.title); stuListView = (ListView)findViewById(R.id.stuListView); //获取当前登录人
     //获得一个SharedPreferences对象,第一个参数为对象文件的名字,第二个参数为对此对象的操作权限,MODE_PRIVATE权限是指只能够被本应用所读写 
     //在系统中有一个lock的文件专门保存本应用的用户登录信息    
        SharedPreferences sp = getSharedPreferences("lock",MODE_PRIVATE);
     //将登录人的用户名取出来 String name
= sp.getString("LoginName","");
     //判断该登录人的用户名是否已经存在,如果不存在,弹框提示请先登录,然后跳转到登录界面
if (name.length()==0){ Toast.makeText(this,"请先登录",Toast.LENGTH_SHORT).show(); Intent intent = new Intent(this,LoginActivity.class); startActivity(intent); }else{
       //如果登录人的用户名已经存在,则获取用户名并在主界面上显示 xxx欢迎你的光临 title.setText(name
+",欢迎您的光临"); } }   
  //主界面上显示一个添加学生信息的按钮,点击按钮,页面跳转到添加学生信息的界面
public void addStu(View view) { Intent intent = new Intent(this,AddStuActivity.class); startActivity(intent); }
  //主界面上显示一个测试监听的按钮,点击按钮,跳转到测试监听的界面
public void test(View view) { Intent intent = new Intent(this,TestActivity.class); startActivity(intent); }   //当当前Activity界面一显示出来时就去调用loadStuList()方法查询出所有的学生及班级信息 @Override protected void onStart(){ super.onStart(); loadStuList(null); } public void loadStuList(View view){ //查询出所有的学生及其班级信息
     //Cursor是结果集游标,通过实例化一个StuDao,调用其中的findStuInfo()方法查询出所有的学生及班级信息,保存在结果集游标中 Cursor cursor = new StuDao(this).findStuInfo();
     //构建适配器所需的数据资源 String[] from
= {"sname","cname","ssex","sage","shobby"}; int[] to ={R.id.stuName,R.id.clsName,R.id.stuSex,R.id.stuAge,R.id.stuHobby};
     //通过适配器给指定的布局文件中填充数据
     //第一个参数是指
 stuListView 所在的 Activity,第二个参数是指 显示stuListView项的布局文件    
     //第四个参数指定cursor中哪些列的数据将绑定(显示)到 UI 中。如果 cursor 无效, 则该参数可为 null。
     //指定用于显示 "from" 参数指定的数据列表的 views。 这些 views 必须都是 TextViews。
     //"from" 参数的前 N 个值(valus)和 "to" 参数的前 N 个 views 是一一对应的关系。如果 cursor 无效,则该参数可为 null。
     //FLAG_AUTO_REQUERY会自动查询如果数据库中的数据发生了变化以实时反映到界面上来,3.0之后废弃了,3.0之后使用FLAG_REGISTER_CONTENT_OBSERVER,
     //NO_SELECTION可以改为这个FLAG_REGISTER_CONTENT_OBSERVER
adapter
= new SimpleCursorAdapter(this,R.layout.layout_stu_list,cursor,from,to,SimpleCursorAdapter.NO_SELECTION); stuListView.setAdapter(adapter); }
   //点击Insert()方法案例按钮,页面跳转到对某个学生进行增删改查的界面
public void test_1(View view){ Intent intent = new Intent(this,InsertActivity.class); startActivity(intent); }
  //安全退出
  //登录人的用户信息都保存在lock文件中,如何对文件进行编辑呢,首先需要创建编辑器Editor
  //通过编辑器的clear()方法将里面的用户信息清空,然后提交一下,
public void safeExit(View view){ //Editor editor = sharedPreferences.edit();//获取编辑器 //SharedPreferences类特别适合用于保存软件配置参数 //使用SharedPreferences保存数据,其背后是用xml文件存放数据,文件存放在/data/data/<package name>/shared_prefs目录下 //getSharedPreferences(name,mode)方法的第一个参数用于指定该文件的名称,名称不用带后缀,后缀会由Android自动加上。
     //方法的第二个参数指定文件的操作模式,共有四种操作模式
//四种模式: //Context.MODE_PRIVATE:为默认操作模式,代表该文件是私有数据,只能被应用本身访问,在该模式下,写入的内容会覆盖原文件的内容 //Context.MODE_APPEND:模式会检查文件是否存在,存在就往文件追加内容,否则就创建新文件. //Context.MODE_WORLD_READABLE和Context.MODE_WORLD_WRITEABLE用来控制其他应用是否有权限读写该文件. SharedPreferences.Editor editor = getSharedPreferences("lock",MODE_PRIVATE).edit(); //清空编辑器 editor.clear(); editor.commit(); //清空Activity栈 MyApplication.getInstance().exit(); } }

3、activity_add_stu.xml

  描述:

    这是添加学生界面布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_add_stu"
    android:orientation="vertical"
    android:layout_marginTop="5dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="添加学生"
        android:textSize="25dp"
        android:gravity="center"
        />
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/sname"
        android:hint="请输入学生姓名"
        />
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/sage"
        android:hint="请输入学生年龄"
        />
    <RadioGroup
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:id="@+id/ssexgroup"
        >
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/sex_1"
            android:text="男"
            android:checked="true"
            />
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/sex_2"
            android:text="女"
            />
    </RadioGroup>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        >
        <CheckBox
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/shobby_1"
            android:text="睡觉"
            />
        <CheckBox
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/shobby_2"
            android:text="美食"
            />
        <CheckBox
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/shobby_3"
            android:text="游戏"
            />
    </LinearLayout>
    <Spinner
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/scno"
        />
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        >
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="添加学生"
            android:onClick="addStu"
            android:layout_weight="1"
            />
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="取消"
            android:onClick="doBack"
            android:layout_weight="1"
            />
    </LinearLayout>
</LinearLayout>

4、AddStuActivity.java

package com.nf.android_sqlite2;

import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.SimpleCursorAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

import com.nf.dao.ClassDao;
import com.nf.dao.StuDao;
import com.nf.entity.TbStu;
import com.nf.utils.MyApplication;

public class AddStuActivity extends Activity {
  //获取布局控件元素
  //下拉列表控件
private Spinner spin_class;
  //适配器
private SimpleCursorAdapter adapter;
  //文本输入框
private EditText sname,sage;
  //单选按钮
private RadioGroup ssexgroup;
  //多选按钮
private CheckBox shobby1,shobby2,shobby3;
  //性别默认为男 String sex
= "男"; private RadioButton sex1,sex2; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_add_stu);
     //将当前Activity放入Activity栈,为了到时候安全退出时,清空当前Activity MyApplication.getInstance().addActivity(
this);
     //编号 spin_class
= (Spinner)findViewById(R.id.scno);
     //姓名 sname
= (EditText)findViewById(R.id.sname);
     //年龄 sage
= (EditText)findViewById(R.id.sage);
     //爱好 shobby1
= (CheckBox)findViewById(R.id.shobby_1); shobby2 = (CheckBox)findViewById(R.id.shobby_2); shobby3 = (CheckBox)findViewById(R.id.shobby_3);
     //性别 sex1
=(RadioButton)findViewById(R.id.sex_1); sex2=(RadioButton)findViewById(R.id.sex_2); ssexgroup = (RadioGroup)findViewById(R.id.ssexgroup);
     //给性别组设置一个选择改变监听器,专门监听RadioGroup组件 ssexgroup.setOnCheckedChangeListener(
new RadioGroup.OnCheckedChangeListener(){
         @Override
public void onCheckedChanged(RadioGroup radioGroup,int i){//注意:这个i的值是很大的,不是1,2,3,4
           if (i==sex1.getId()){
            //如果选中的是男,就获取其id RadioButton rb
= (RadioButton)findViewById(i);
            //通过id获取其内容并转化为字符串 sex
= rb.getText().toString();
            //弹出提示 Toast.makeText(AddStuActivity.
this,"男 = "+sex,Toast.LENGTH_SHORT).show(); } if (i==sex2.getId()){ RadioButton rb = (RadioButton)findViewById(i); sex = rb.getText().toString(); Toast.makeText(AddStuActivity.this,"女 = "+sex,Toast.LENGTH_SHORT).show(); } } }); }
  //onResume()是当该activity与用户能进行交互时被执行,用户可以获得activity的焦点,能够与用户交互。 @Override
protected void onResume(){ super.onResume(); //取出班级并绑定到Spinner中
     //调用班级ClassDao()的getClassCursor()方法查询出所有的班级,并保存在结果集游标中
Cursor cursor = new ClassDao(this).getClassCursor();
     //设置适配器资源 String[] from
= {"_id","cname"}; int[] to = {R.id.cno,R.id.cname};
     //给spin_class绑定适配器,将结果集游标里的数据填入到下拉列表中 adapter
= new SimpleCursorAdapter(this,R.layout.layout_spinner_class,cursor,from,to,SimpleCursorAdapter.NO_SELECTION); spin_class.setAdapter(adapter); } //添加学生 public void addStu(View view){
     //获取id为sname的文本输入框的文本内容并转化为字符串 String name
= sname.getText().toString();
     //同上
int age = Integer.parseInt(sage.getText().toString()); String hobby = ""; if (shobby1.isChecked()){ hobby = shobby1.getText()+","; } if (shobby2.isChecked()){ hobby = hobby+shobby2.getText()+","; } if (shobby3.isChecked()){ hobby = hobby+shobby3.getText()+","; }
     //只要选择了某个或多个兴趣,就将所选中的兴趣通过截取字符串的方式截取下来,减一是为了去掉最后一个逗号
if (hobby.length()>0){ hobby = hobby.substring(0,hobby.length()-1); } //取出下拉列表中选中的项,你选中了哪项TextView就将哪个TextView取出来
     LinearLayout item = (LinearLayout)spin_class.getSelectedView();
     //通过取出的项,进一步取到它的id名  TextView txt_cno
= (TextView)item.findViewById(R.id.cno);
     //根据id获取它的文本内容并转化为字符串,然后又通过Integer.parseInt()方法将其转化为int类型
int cno = Integer.parseInt(txt_cno.getText().toString());      //将学生的编号0开始和输入的名字,输入的年龄,选择好的性别和爱好和班级编号一起封装到TbStu TbStu stu = new TbStu(0,name,age,sex,hobby,cno);
     //调用stuDao()的addStu()方法将学生信息添加,如果返回的是true,则弹出添加学生成功
if (new StuDao(this).addStu(stu)){ Toast.makeText(this,"添加学生成功",Toast.LENGTH_SHORT).show(); }else{ Toast.makeText(this,"添加学生失败",Toast.LENGTH_SHORT).show(); } }
  //点击取消按钮则关闭当前Activity
public void doBack(View view){ this.finish(); } }

5、activity_test.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_add_stu"
    android:orientation="vertical"
    android:layout_marginTop="5dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <RadioGroup
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:id="@+id/ssexgroup"
        >
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/sex_1"
            android:text="男"
            android:checked="true"
            />
        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/sex_2"
            android:text="女"
            />
    </RadioGroup>
</LinearLayout>

6、TestActivity.java

package com.nf.android_sqlite2;

import android.app.Activity;
import android.os.Bundle;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;

public class TestActivity extends Activity {
    private RadioGroup ssexgroup;
    String sex = "男";
    private RadioButton sex1,sex2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test);
        sex1=(RadioButton)findViewById(R.id.sex_1);
        sex2=(RadioButton)findViewById(R.id.sex_2);
        ssexgroup = (RadioGroup)findViewById(R.id.ssexgroup);
     //主要是这个事件 ssexgroup.setOnCheckedChangeListener(
new RadioGroup.OnCheckedChangeListener(){ @Override public void onCheckedChanged(RadioGroup radioGroup,int i){//注意:这个i的值是很大的,不是1,2,3,4 RadioButton rb = (RadioButton)findViewById(i); sex = rb.getText().toString(); if (i==sex1.getId()){ Toast.makeText(TestActivity.this,"男 = "+sex,Toast.LENGTH_SHORT).show(); } if (i==sex2.getId()){ Toast.makeText(TestActivity.this,"女 = "+sex,Toast.LENGTH_SHORT).show(); } } }); } }

7、activity_login.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_login"
    android:orientation="vertical"
    android:layout_margin="10dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="用户登录"
        android:textSize="25dp"
        android:gravity="center"
        />
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/uname"
        android:hint="请输入用户名"
        />
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/upwd"
        android:hint="请输入密码"
        android:inputType="textPassword"
        />
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        >
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="登录"
            android:onClick="doLogin"
            android:layout_weight="1"
            />
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="退出"
            android:onClick="doExit"
            android:layout_weight="1"
            />
    </LinearLayout>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/registerLink"
        android:gravity="right"
        android:text="新用户注册"
        android:onClick="toRegister"
        android:textSize="20dp"
        android:layout_marginTop="10dp"
        android:layout_marginRight="10dp"
        android:textColor="@android:color/holo_blue_light"
        />
</LinearLayout>

8、LoginActivity.java

package com.nf.android_sqlite2;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import com.nf.dao.UserDao;
import com.nf.entity.Users;
import com.nf.utils.MyApplication;

public class LoginActivity extends Activity {
    private TextView registerLink;
    private EditText uname,upwd;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        //将当前Activity加入到自定义栈中
        MyApplication.getInstance().addActivity(this);

        registerLink = (TextView)findViewById(R.id.registerLink);
     //给用户注册的连接设置下划线 registerLink.getPaint().setFlags(Paint.UNDERLINE_TEXT_FLAG); registerLink.getPaint().setAntiAlias(
true);//抗锯齿      //获取到用户名和密码 uname = (EditText)findViewById(R.id.uname); upwd = (EditText)findViewById(R.id.upwd); } //点击登录 public void doLogin(View view){
     //当点击登录时获取到用户输入的文本内容并转化为字符串类型 String name
= uname.getText().toString(); String pwd = upwd.getText().toString();
     //通过调用UserDao()的doLogin()方法将用户名和密码传入进去,然后去那边判断用户名和密码是否已经存在,如果存在则会返回封装在user中的用户编号和用户名,密码就不用返回了 Users user
= new UserDao(this).doLogin(name,pwd);//调用方法进行登录验证
     //只要user中不为空 if (user!=null){ //保留登录状态
       //先找到那个专门保存用户信息的lock文件 SharedPreferences sp = getSharedPreferences("lock",MODE_PRIVATE);
       //通过创建编辑器 SharedPreferences.Editor editor
= sp.edit();
       //调用编辑器的putString()方法,将用户编号和用户名添加到lock文件中 editor.putString(
"LoginNo",user.getUno()+""); editor.putString("LoginName",user.getUname());
       //提交信息 editor.commit();
//跳转到主页面 Intent intent = new Intent(this,MainActivity.class); startActivity(intent); }else{ Toast.makeText(this,"用户名和密码错误",Toast.LENGTH_SHORT).show(); } } //退出 public void doExit(View view){ this.finish(); MyApplication.getInstance().exit(); } //点击注册按钮时 public void toRegister(View view){
     //在登录界面创建一个对话框 AlertDialog.Builder builder
= new AlertDialog.Builder(this);
     //设置对话框的标题 builder.setTitle(
"用户注册");
     //通过投影的方式将layout_register_user的布局投影到当前页面 View dialogView
= LayoutInflater.from(this).inflate(R.layout.layout_register_user,null);
     //绑定id
final EditText uname = (EditText)dialogView.findViewById(R.id.uname); final EditText upwd = (EditText)dialogView.findViewById(R.id.upwd);
     //然后又将投影得到的布局绑定到对话框 builder.setView(dialogView);
     //给对话框设置一个注册按钮并设置单击监听事件的方法
       builder.setPositiveButton(
"注册",new DialogInterface.OnClickListener(){ @Override public void onClick(DialogInterface dialogInterface,int i){
          //点击注册按钮后调用UserDao()中的addUser()方法,传入一个封装的User对象,将用户编号,用户名,用户密码传过去,返回true则提示注册成功
if (new UserDao(LoginActivity.this).addUser(new Users(0,uname.getText().toString(),upwd.getText().toString()))){ Toast.makeText(LoginActivity.this,"注册成功",Toast.LENGTH_SHORT).show(); }else{ Toast.makeText(LoginActivity.this,"注册失败",Toast.LENGTH_SHORT).show(); } } });
     //给对话框设置取消按钮 builder.setNeutralButton(
"取消",null);
     //创建对话框并显示出来 builder.create().show(); } }

9、activity_insert.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_insert"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Insert()案例"
        android:onClick="test_Insert"
        />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Update()案例"
        android:onClick="test_Update"
        />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Delete()案例"
        android:onClick="test_Delete"
        />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Query()案例"
        android:onClick="test_Query"
        />
</LinearLayout>

10、InsertActivity.java

package com.nf.android_sqlite2;

import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

import com.nf.dao.DbHelper;

public class InsertActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_insert);
    }
    //Insert()方法实现添加数据
   //点击添加数据 public void test_Insert(View view){
     //实例化SQLiteDatabase对象 SQLiteDatabase sdb
= DbHelper.getInstance(this).getReadableDatabase();
     //ContentValues是一种存储机制,只能存储基本类型的数据,不能存储对象信息,是通过键值对的方式存储 ContentValues values
= new ContentValues();
     //通过put()的方法,向ContentValues中存入一个学生信息 values.put(
"pname","Marry"); values.put("page",24); values.put("psex","女");
     //调用DbHelper中的insert()方法,将学生信息传过去添加到SQLite数据库中
     //第一个参数是表名,表示给SQLite数据库中的哪个表添加数据,第二个参数可能代表字段名称,表示给该表的某个字段插入某值 sdb.insert(
"Person",null,values); Toast.makeText(this,"添加Person成功!",Toast.LENGTH_SHORT).show(); } //Update()方法修改数据 public void test_Update(View view){
     //同上 SQLiteDatabase sdb
= DbHelper.getInstance(this).getReadableDatabase(); ContentValues values = new ContentValues();
     //将年龄设置为25 values.put(
"page","25");
     //调用update()方法,修改person表中名字为Marry的的年龄,将值设置为25 sdb.update(
"Person",values,"pname='Marry'",null); } //Delete()方法删除数据 public void test_Delete(View view){
     //同上 SQLiteDatabase sdb
= DbHelper.getInstance(this).getReadableDatabase();
     //调用delete()方法,删除Person表中名字为Marry的人的信息 sdb.delete(
"Person","pname='Marry'",null); }
//Query()方法查询数据 public void test_Query(View view){
     //同上 SQLiteDatabase sdb
= DbHelper.getInstance(this).getReadableDatabase();
     //调用query()查询Person表中年龄为22到25的人的信息,并倒序排序 Cursor cursor
= sdb.query("Person",null,"page>=? and page<=?",new String[]{"22","25"},null,null,"page desc");
     //循环遍历结果集游标
while(cursor.moveToNext()){
        //通过游标的getColumnIndex()获取列名为“_id”的编号信息
int pno = cursor.getInt(cursor.getColumnIndex("_id"));
       //同上 String pname
= cursor.getString(cursor.getColumnIndex("pname")); int page = cursor.getInt(cursor.getColumnIndex("page")); String psex = cursor.getString(cursor.getColumnIndex("psex"));
       //通过日志的形式输出 Log.i(
"Query Person",pno+","+pname+","+page+","+psex); }
     //关闭游标 cursor.close(); } }

 

11、ClassDao.java

package com.nf.dao;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

/**
 * Created by Admin on 2017/12/13.
 */

public class ClassDao {
    private SQLiteDatabase sdb;
    public ClassDao(Context context){
     //实例化SQLiteDatabase DbHelper dbHelper
= DbHelper.getInstance(context); sdb = dbHelper.getReadableDatabase(); } public Cursor getClassCursor(){
     //构建查询语句,查询班级表中的所有信息 String sql
= "select * from tb_class";
     //调用rawQuery()方法进行查询,并将返回的班级信息返回给调用者
return sdb.rawQuery(sql,null); } }

12、DbHelper.java

package com.nf.dao;

import android.content.Context;
import android.database.DatabaseErrorHandler;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.text.style.TtsSpan;
import android.util.Log;

public class DbHelper extends SQLiteOpenHelper{
   //数据库名称
    private static final String DATABASE_NAME = "mydb.db";
  //数据库版本
private static final int VERSION = 1;   //初始化数据库 public DbHelper(Context context) { super(context,DATABASE_NAME,null,VERSION ); } public DbHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version, DatabaseErrorHandler errorHandler) { super(context,DATABASE_NAME,null,VERSION ); }    @Override public void onCreate(SQLiteDatabase db) {
     //创建一个Person表 String sql
= "create table if not exists Person(" + "_id integer primary key," + "pname text," + "page integer," + "psex text" + ")";
     //执行sql语句 db.execSQL(sql);
     //给Person表中插入一条数据 sql
= "insert into Person(pname,page,psex)values('Lucy',23,'女')"; db.execSQL(sql); Log.i("DbHelper","创建数据表Person成功"); //创建用户表 sql = "create table if not exists Users(" + "_id integer primary key," + "uname text not null," + "upwd text not null" + ")"; db.execSQL(sql); sql = "insert into Users(uname,upwd) values('admins','admins')"; db.execSQL(sql); Log.i("create DB","创建用户成功"); //创建班级表和学生表 sql = "create table if not exists tb_class(" + "_id integer primary key," + "cname text not null" + ")"; db.execSQL(sql); sql = "insert into tb_class(cname) values('S1T01')"; db.execSQL(sql); sql = "insert into tb_class(cname) values('S1T02')"; db.execSQL(sql); sql = "insert into tb_class(cname) values('S1T03')"; db.execSQL(sql); Log.i("create DB","创建班级成功"); sql = "create table if not exists tb_stu(" + "_id integer primary key," + "sname text not null," + "sage integer," + "ssex text," + "shobby text," + "scno integer," + "foreign key(scno) references tb_class(_id)" + ")"; db.execSQL(sql); sql = "insert into tb_stu(sname,sage,ssex,shobby,scno)values('张三',23,'男','睡觉',1)"; db.execSQL(sql); sql = "insert into tb_stu(sname,sage,ssex,shobby,scno)values('Lucys',21,'女','美食',1)"; db.execSQL(sql); Log.i("create DB","创建用户,班级,学生表成功"); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
     //上面的onCreate()方法只会执行一次,一次之后就不会执行那个方法了,但可以通过这个方法做一些修改的操作
     //执行一些修改操作 String sql = "drop table Person"; db.execSQL(sql);
     //重新构建上面的表结构 onCreate(db); }
//提供一个方法获取DbHelper实例
  //私有化
private static DbHelper dbHelper;
  //提供公共的访问方法
public static synchronized DbHelper getInstance(Context context){
     //当外界调用这个方法时,如果发现上面的表结构还未创建,则会实例化这个DbHelper,这样就保证了表结构是存在的
if (dbHelper == null){ dbHelper = new DbHelper(context); } return dbHelper; } }

13、StuDao.java

package com.nf.dao;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import com.nf.entity.TbStu;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Created by Admin on 2017/12/13.
 */

public class StuDao {
    private SQLiteDatabase sdb;
    public StuDao(Context context){
        DbHelper dbHelper = DbHelper.getInstance(context);
        sdb = dbHelper.getReadableDatabase();
    }
    //添加学生
  //添加成功返回true
public boolean addStu(TbStu stu){
     //构建插入语句 String sql
= "insert into tb_stu(sname,sage,ssex,shobby,scno) values(?,?,?,?,?)"; try {
       //执行查询 sdb.execSQL(sql,
new Object[]{stu.getSname(), stu.getSage(), stu.getSsex(), stu.getShobby(), stu.getScno()}); return true; }catch (Exception e){ e.printStackTrace(); } return false; } //查询出所有的学生信息
  //查询成功返回结果集游标,结果集游标里保存着学生信息 public Cursor findStuInfo(){
     //构建联合查询语句 String sql
= "select s.*,c.cname from tb_stu s left join tb_class c on s.scno=c._id";
     //rawQuery()方法专门是用于查询 Cursor cursor
= sdb.rawQuery(sql,null); return cursor; }
  
//查询出所有的学生信息
  //比上面的查询复杂,但灵活度高 public List<Map<String,Object>> findStuInfo2(){
     //构建查询语句 String sql
= "select s.*,c.cname from tb_stu s left join tb_class c on s.scno = c._id";
     //将查询到的信息放入结果集游标 Cursor cursor
= sdb.rawQuery(sql,null);
     //构建集合 List
<Map<String,Object>> list = new ArrayList<Map<String,Object>>();
     //获取游标的列名 String[] columNames
= cursor.getColumnNames();
     //遍历游标
while (cursor.moveToNext()){ Map<String,Object> map = new HashMap<String,Object>(); for (int i=0;i<columNames.length;i++){
         //根据游标中的列名得到所有列中的信息,放入map中,在将map添加到list中,返回list map.put(columNames[i],cursor.getString(cursor.getColumnIndex(columNames[i]))); } list.add(map); }
return list; } }

14、UserDao.java

package com.nf.dao;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import com.nf.entity.Users;

import java.nio.file.attribute.UserPrincipalLookupService;

/**
 * Created by Admin on 2017/12/13.
 */

public class UserDao {
    private SQLiteDatabase sdb;
    public UserDao(Context context){
     //实例化SQLiteDatabase对象 DbHelper dbHelper
= DbHelper.getInstance(context); sdb = dbHelper.getReadableDatabase(); } //验证用户名和密码
  //验证成功则返回用户编号和用户名 public Users doLogin(String name,String pwd){
     //构建查询语句,根据名字查询用户信息 String sql
= "select * from Users where uname = ?"; Cursor cursor = sdb.rawQuery(sql,new String[]{name}); while(cursor.moveToNext()){ int uno = cursor.getInt(cursor.getColumnIndex("_id")); String uname = cursor.getString(cursor.getColumnIndex("uname")); String upwd = cursor.getString(cursor.getColumnIndex("upwd")); if (uname.equals(name)&&upwd.equals(pwd)){ return new Users(uno,uname,null); } } return null; } //添加用户 public boolean addUser(Users user){ String sql = "insert into Users(uname,upwd)values(?,?)"; try{ sdb.execSQL(sql,new String[]{user.getUname(),user.getUpwd()}); return true; }catch(Exception ex){ ex.printStackTrace(); } return false; } }

 

15、TbClass.java

package com.nf.entity;

/**
 * Created by Admin on 2017/12/13.
 */

public class TbClass {
    private int cno;
    private String cname;

    public TbClass() {
    }

    public TbClass(int cno, String cname) {
        this.cno = cno;
        this.cname = cname;
    }

    public int getCno() {
        return cno;
    }

    public void setCno(int cno) {
        this.cno = cno;
    }

    public String getCname() {
        return cname;
    }

    public void setCname(String cname) {
        this.cname = cname;
    }
}

16、TbStu.java

package com.nf.entity;

public class TbStu {
    private int sno;
    private String sname;
    private int sage;
    private String ssex;
    private String shobby;
    private int scno;

    public TbStu() {
    }

    public TbStu(int sno, String sname, int sage, String ssex, String shobby, int scno) {
        this.sno = sno;
        this.sname = sname;
        this.sage = sage;
        this.ssex = ssex;
        this.shobby = shobby;
        this.scno = scno;
    }

    public int getSno() {
        return sno;
    }

    public void setSno(int sno) {
        this.sno = sno;
    }

    public String getSname() {
        return sname;
    }

    public void setSname(String sname) {
        this.sname = sname;
    }

    public int getSage() {
        return sage;
    }

    public void setSage(int sage) {
        this.sage = sage;
    }

    public String getSsex() {
        return ssex;
    }

    public void setSsex(String ssex) {
        this.ssex = ssex;
    }

    public String getShobby() {
        return shobby;
    }

    public void setShobby(String shobby) {
        this.shobby = shobby;
    }

    public int getScno() {
        return scno;
    }

    public void setScno(int scno) {
        this.scno = scno;
    }
}

17、Users.java

package com.nf.entity;

/**
 * Created by Admin on 2017/12/13.
 */

public class Users {
    private int uno;
    private String uname;
    private String upwd;

    public Users() {
    }

    public Users(int uno, String uname, String upwd) {
        this.uno = uno;
        this.uname = uname;
        this.upwd = upwd;
    }

    public int getUno() {
        return uno;
    }

    public void setUno(int uno) {
        this.uno = uno;
    }

    public String getUname() {
        return uname;
    }

    public void setUname(String uname) {
        this.uname = uname;
    }

    public String getUpwd() {
        return upwd;
    }

    public void setUpwd(String upwd) {
        this.upwd = upwd;
    }
}

18、MyApplication.java

package com.nf.utils;

import android.app.Activity;
import android.app.Application;

import java.util.LinkedList;
import java.util.List;

//Application配置全局Context
public class MyApplication extends Application{
    private List<Activity> mList = new LinkedList<Activity>();
    private static MyApplication instance = null;
    private MyApplication(){}

    //synchronized同步锁,实现单例效果
    //方法上加static关键词代表这个方法属于类的,这样才可以在MainActivity.java中通过MyApplication.getInstance().addActivity(this);的方式调用
    public synchronized static MyApplication getInstance(){
        if (null == instance){
            //如果实例还没有创建,则创建实例;若实例已经被创建,则直接返回之前创建的实例
            instance = new MyApplication();
        }
        return instance;
    }
    //获取Activity的方法
    //在MainActivity.jaava类中通过MyApplication.getInstance().addActivity(this);传入this,到这个方法获得一个Activity的类
    public void addActivity(Activity activity){
        //将Activity放入到list集合里,再进行循环遍历
        mList.add(activity);
    }
    //安全退出的方法
    public void exit(){
        try{
            //循环遍历list中收集的所有Activity
            for (Activity activity:mList){
                //将集合中的Activity杀死
                if (activity != null)
                    activity.finish();
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            //系统退出,在退出之前将所有的Activity杀死,实现安全退出
            System.exit(0);
        }
    }

    //当系统内存不足要将后台程序杀死时,且在最后一个后台程序被杀死时会自动调用这个方法,释放UI使用的资源,进行垃圾
    //拓展:onTrimMemory()方法。
    public void onLowMemory(){
        super.onLowMemory();
        //系统垃圾回收
        System.gc();
    }

}

19、layout_register_user.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="10dp">
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/uname"
        android:hint="请输入用户名"
        />
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/upwd"
        android:hint="请输入密码"
        android:inputType="textPassword"
        />
</LinearLayout>

20、layout_spinner_class.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="50dp"
        android:id="@+id/cno"
        android:visibility="invisible"
        />
    <TextView
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:id="@+id/cname"
        android:gravity="center_vertical"
        />
</LinearLayout>

21、layout_stu_list.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/holo_green_light"
    >
    <ImageView
        android:layout_width="60dp"
        android:layout_height="70dp"
        android:id="@+id/userImage"
        android:src="@mipmap/ic_launcher"
        />
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="5dp"
        android:orientation="vertical"
        >
        <LinearLayout
            android:layout_width="match_parent"
            android:orientation="horizontal"
            android:layout_height="33dp"
            >
            <TextView
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:id="@+id/stuName"
                android:text="姓名:张三"
                android:textSize="20dp"
                android:gravity="center_vertical"
                android:layout_weight="1"
                />
            <TextView
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:id="@+id/clsName"
                android:text="班级:S1T01"
                android:textSize="20dp"
                android:gravity="center_vertical"
                android:layout_weight="1"
                />
        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="2dp"
            android:background="@android:color/darker_gray"
            />
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="35dp"
                android:orientation="horizontal"
                >
                <TextView
                    android:layout_width="0dp"
                    android:layout_height="35dp"
                    android:id="@+id/stuSex"
                    android:gravity="center_vertical"
                    android:layout_weight="1"
                    android:text="性别:男"
                    android:textSize="18dp"
                    />
                <TextView
                    android:layout_width="0dp"
                    android:layout_height="35dp"
                    android:id="@+id/stuAge"
                    android:layout_weight="1"
                    android:gravity="center_vertical"
                    android:textSize="18dp"
                    android:text="23"
                    />
                <TextView
                    android:layout_width="0dp"
                    android:layout_height="35dp"
                    android:id="@+id/stuHobby"
                    android:layout_weight="2"
                    android:gravity="center_vertical"
                    android:textSize="18dp"
                    android:text="睡觉"
                    />
        </LinearLayout>
    </LinearLayout>
</LinearLayout>

www.bkjia.comtruehttp://www.bkjia.com/Androidjc/1284008.htmlTechArticleAndroid开发, 目录截图: 1、activity_main.xml 主界面效果: ? xml version="1.0" encoding="utf-8" ? ScrollView xmlns:android ="http://schemas.android.com/apk/res/andro...

相关文章

相关搜索: android开发

帮客评论

视觉看点