实例解析Android系统中的ContentProvider组件用法

<provider       android:name="com.android.xiong.conentprovidertesta.FirstContentProvider"       android:authorities="com.android.xiong.ConentProviderTestA.firstContentProvider"       android:exported="true" > </provider> 

实例如下

A程序:
UserInfo.java

package com.android.xiong.conentprovidertesta;  import android.content.ContentProvider; import android.content.ContentValues; import android.content.UriMatcher; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.net.Uri;  public class FirstContentProvider extends ContentProvider {    // UriMatcher类主要用来匹配Uri   private static final UriMatcher uriMatcher = new UriMatcher(       UriMatcher.NO_MATCH);   private MySqlite mysqlite;   static {     // 注册向外部程序提供的Uri     uriMatcher.addURI(UserInfo.AUTOR, "userinfo", 1);     uriMatcher.addURI(UserInfo.AUTOR, "userinfoall", 2);   }   //删除数据   @Override   public int delete(Uri uri, String selection, String[] selectionArgs) {     int number = 0;     if (uriMatcher.match(uri) == 1) {       // 根据条件删除数据,并获取删除的行数       number = mysqlite.getReadableDatabase().delete("user_info",           selection, selectionArgs);     }     // 通知数据已经改变     getContext().getContentResolver().notifyChange(uri, null);     return number;   }    @Override   public String getType(Uri uri) {      return null;   }   //插入数据   @Override   public Uri insert(Uri uri, ContentValues values) {     String name = values.getAsString(UserInfo.User.NAME).toString();     String age = values.getAsInteger(UserInfo.User.AGE).toString();     String maxId = "select max(id) id from user_info";     Cursor cursor = mysqlite.getReadableDatabase().rawQuery(maxId, null);     cursor.moveToFirst();     int userid = cursor.getInt(0) + 1;     if (uriMatcher.match(uri) == 1) {        mysqlite.getWritableDatabase().execSQL(           "insert into user_info values(?,?,?)",           new String[] { String.valueOf(userid), name, age });     }     return uri;   }    // 连接数据库   @Override   public boolean onCreate() {     mysqlite = new MySqlite(getContext(), "userinfo.db", null, 1);     return true;   }   //查询数据   @Override   public Cursor query(Uri uri, String[] projection, String selection,       String[] selectionArgs, String sortOrder) {     SQLiteDatabase sqlite = mysqlite.getReadableDatabase();     String str = "select name,age from user_info";     if (uriMatcher.match(uri) == 1) {       str += " where " + selection;     }     Cursor cursor = sqlite.rawQuery(str, selectionArgs);     return cursor;   }   //修改数据   @Override   public int update(Uri uri, ContentValues values, String selection,       String[] selectionArgs) {     SQLiteDatabase sqlite = mysqlite.getReadableDatabase();     int number = 0;     if (uriMatcher.match(uri) == 1) {       number = sqlite.update("user_info", values, selection,           selectionArgs);     }     return number;   }  } 

package com.android.xiong.conentprovidertesta;  import android.content.ContentProvider; import android.content.ContentValues; import android.content.UriMatcher; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.net.Uri;  public class FirstContentProvider extends ContentProvider {    // UriMatcher类主要用来匹配Uri   private static final UriMatcher uriMatcher = new UriMatcher(       UriMatcher.NO_MATCH);   private MySqlite mysqlite;   static {     // 注册向外部程序提供的Uri     uriMatcher.addURI(UserInfo.AUTOR, "userinfo", 1);     uriMatcher.addURI(UserInfo.AUTOR, "userinfoall", 2);   }   //删除数据   @Override   public int delete(Uri uri, String selection, String[] selectionArgs) {     int number = 0;     if (uriMatcher.match(uri) == 1) {       // 根据条件删除数据,并获取删除的行数       number = mysqlite.getReadableDatabase().delete("user_info",           selection, selectionArgs);     }     // 通知数据已经改变     getContext().getContentResolver().notifyChange(uri, null);     return number;   }    @Override   public String getType(Uri uri) {      return null;   }   //插入数据   @Override   public Uri insert(Uri uri, ContentValues values) {     String name = values.getAsString(UserInfo.User.NAME).toString();     String age = values.getAsInteger(UserInfo.User.AGE).toString();     String maxId = "select max(id) id from user_info";     Cursor cursor = mysqlite.getReadableDatabase().rawQuery(maxId, null);     cursor.moveToFirst();     int userid = cursor.getInt(0) + 1;     if (uriMatcher.match(uri) == 1) {        mysqlite.getWritableDatabase().execSQL(           "insert into user_info values(?,?,?)",           new String[] { String.valueOf(userid), name, age });     }     return uri;   }    // 连接数据库   @Override   public boolean onCreate() {     mysqlite = new MySqlite(getContext(), "userinfo.db", null, 1);     return true;   }   //查询数据   @Override   public Cursor query(Uri uri, String[] projection, String selection,       String[] selectionArgs, String sortOrder) {     SQLiteDatabase sqlite = mysqlite.getReadableDatabase();     String str = "select name,age from user_info";     if (uriMatcher.match(uri) == 1) {       str += " where " + selection;     }     Cursor cursor = sqlite.rawQuery(str, selectionArgs);     return cursor;   }   //修改数据   @Override   public int update(Uri uri, ContentValues values, String selection,       String[] selectionArgs) {     SQLiteDatabase sqlite = mysqlite.getReadableDatabase();     int number = 0;     if (uriMatcher.match(uri) == 1) {       number = sqlite.update("user_info", values, selection,           selectionArgs);     }     return number;   }  } 

package com.android.xiong.conentprovidertesta;  import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.database.sqlite.SQLiteOpenHelper;  public class MySqlite extends SQLiteOpenHelper {    static final String sql = "create table user_info(id int,name varchar(30),age int)";    public MySqlite(Context context, String name, CursorFactory factory,       int version) {     super(context, name, factory, version);     // TODO Auto-generated constructor stub   }    @Override   public void onCreate(SQLiteDatabase db) {     //创建数据表     db.execSQL(sql);    }    @Override   public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {     // TODO Auto-generated method stub    }  } 

package com.android.xiong.conentprovidertesta;  import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.database.sqlite.SQLiteOpenHelper;  public class MySqlite extends SQLiteOpenHelper {    static final String sql = "create table user_info(id int,name varchar(30),age int)";    public MySqlite(Context context, String name, CursorFactory factory,       int version) {     super(context, name, factory, version);     // TODO Auto-generated constructor stub   }    @Override   public void onCreate(SQLiteDatabase db) {     //创建数据表     db.execSQL(sql);    }    @Override   public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {     // TODO Auto-generated method stub    }  } 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   xmlns:tools="http://schemas.android.com/tools"   android:layout_width="match_parent"   android:layout_height="match_parent"   android:orientation="vertical"   tools:context=".MainActivity" >    <TextView     android:id="@+id/txt1"     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:gravity="center_horizontal"     android:text="添加信息"     android:textSize="20dp" />    <EditText     android:id="@+id/ed1"     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:hint="添加name" />    <EditText     android:id="@+id/ed2"     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:hint="添加age"     android:inputType="number" />    <Button     android:id="@+id/bt1"     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:text="提交数据" />      <ListView       android:id="@+id/lists"       android:layout_width="match_parent"       android:layout_height="wrap_content" >     </ListView>   </LinearLayout> 

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   android:layout_width="match_parent"   android:layout_height="match_parent"   android:orientation="horizontal" >   <TextView      android:id="@+id/item_txt1"     android:layout_width="wrap_content"     android:layout_height="wrap_content"/>     <TextView      android:id="@+id/item_txt2"     android:layout_width="wrap_content"     android:layout_height="wrap_content"/>     </LinearLayout> 

package com.android.xiong.contentprovidertestb;  //向外部程序提供一个工具类 public class UserInfo {    // 获取ContentProvider的“域名”   public static final String AUTOR = "com.android.xiong.ConentProviderTestA.firstContentProvider";      //定义一个静态内部类，提供ContentProvider可操作的列   public static final class User {          public static final String ID="id";     public static final String NAME="name";     public static final String AGE="age";     //定义该content提供服务的一个Uri     public static final String uri="content://"+AUTOR+"/userinfo";     public static final String uriall="content://"+AUTOR+"/userinfoall";        }  } 

package com.android.xiong.contentprovidertestb;  import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map;  import android.app.Activity; import android.content.ContentValues; import android.database.Cursor; import android.net.Uri; import android.os.Bundle; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.ListView; import android.widget.ScrollView; import android.widget.SimpleAdapter; import android.widget.Toast;  public class MainActivity extends Activity {    private Button bt1, bt2, bt3, bt4;   private EditText ed1, ed2;   private ListView list1;   private ScrollView sc1;    @Override   protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);     bt1 = (Button) findViewById(R.id.bt1);     bt2 = (Button) findViewById(R.id.bt2);     bt3 = (Button) findViewById(R.id.bt3);     bt4 = (Button) findViewById(R.id.bt4);     ed1 = (EditText) findViewById(R.id.ed1);     ed2 = (EditText) findViewById(R.id.ed2);     list1 = (ListView) findViewById(R.id.list);     // 显示所有数据     list1.setAdapter(adapter(0));     sc1 = (ScrollView) findViewById(R.id.scr1);     // 向添加ContentProviderA应用的数据     bt1.setOnClickListener(new OnClickListener() {        @Override       public void onClick(View v) {         String eds1 = ed1.getText().toString();         String eds2 = ed2.getText().toString();         ContentValues content = new ContentValues();         if (!eds1.equals("") && !eds2.equals("")) {           content.put(UserInfo.User.NAME, eds1);           content.put(UserInfo.User.AGE, eds2);           MainActivity.this.getContentResolver().insert(               Uri.parse(UserInfo.User.uri), content);           Toast.makeText(MainActivity.this, "数据插入成功",               Toast.LENGTH_LONG).show();           // 刷新ListView界面           list1.setAdapter(adapter(0));         } else {           Toast.makeText(MainActivity.this, "name和age不能为空",               Toast.LENGTH_LONG).show();         }        }     });     // 根据条件删除ContentProviderA应用的数据     bt2.setOnClickListener(new OnClickListener() {        @Override       public void onClick(View v) {         String eds1 = ed1.getText().toString();         String eds2 = ed2.getText().toString();         if (!eds1.equals("") || !eds2.equals("")) {           HashMap<String, String[]> wheres = wheres(eds1, eds2);           String sql = wheres.get("sql")[0];           String[] selectags = wheres.get("selectages");           MainActivity.this.getContentResolver().delete(               Uri.parse(UserInfo.User.uri), sql, selectags);          } else {           Toast.makeText(MainActivity.this, "请输入删除条件",               Toast.LENGTH_LONG).show();         }         // 刷新ListView界面         list1.setAdapter(adapter(0));       }     });     // 修改数据     bt3.setOnClickListener(new OnClickListener() {        @Override       public void onClick(View v) {         String eds1 = ed1.getText().toString();         String eds2 = ed2.getText().toString();         ContentValues values = new ContentValues();         // 根据条件将列修改为xiong,23         values.put(UserInfo.User.NAME, "xiong");         values.put(UserInfo.User.AGE, "23");         if (!eds1.equals("") || !eds2.equals("")) {           HashMap<String, String[]> wheres = wheres(eds1, eds2);           String sql = wheres.get("sql")[0];           String[] selectags = wheres.get("selectages");           int i=MainActivity.this.getContentResolver().update(               Uri.parse(UserInfo.User.uri), values, sql,               selectags);          } else {           Toast.makeText(MainActivity.this, "请输入删除条件",               Toast.LENGTH_LONG).show();         }         // 刷新ListView界面         list1.setAdapter(adapter(0));        }     });     // 根据条件查询ContentProviderA应用的数据     bt4.setOnClickListener(new OnClickListener() {       @Override       public void onClick(View v) {         if (!ed1.getText().toString().equals("")             || !ed2.getText().toString().equals(""))           list1.setAdapter(adapter(1));         else           list1.setAdapter(adapter(0));       }     });   }    // 用来判别条件   public HashMap<String, String[]> wheres(String eds1, String eds2) {     HashMap<String, String[]> where = new HashMap<String, String[]>();     if (!eds1.equals("") && !eds2.equals("")) {       String[] sql = { UserInfo.User.NAME + "=? and " + UserInfo.User.AGE           + " =?" };       String[] selectages = { eds1, eds2 };       where.put("sql", sql);       where.put("selectages", selectages);      }     if (!eds1.equals("") && eds2.equals("")) {       String[] sql = { UserInfo.User.NAME + "=? " };       String[] selectages = { eds1 };       where.put("sql", sql);       where.put("selectages", selectages);      }     if (eds1.equals("") && !eds2.equals("")) {       String[] sql = { UserInfo.User.AGE + " =?" };       String[] selectages = { eds2 };       where.put("sql", sql);       where.put("selectages", selectages);      }     return where;   }    // 用来显示数据   public SimpleAdapter adapter(int i) {     Cursor cs = MainActivity.this.getContentResolver().query(         Uri.parse(UserInfo.User.uriall), null, null, null, null);     String eds1 = ed1.getText().toString();     String eds2 = ed2.getText().toString();     if (i == 1) {       if (!eds1.equals("") || !eds2.equals("")) {         HashMap<String, String[]> wheres = wheres(eds1, eds2);         String sql = wheres.get("sql")[0];         String[] selectags = wheres.get("selectages");         cs = MainActivity.this.getContentResolver().query(             Uri.parse(UserInfo.User.uri), null, sql, selectags,             null);       }      }      List<Map<String, Object>> lists = new ArrayList<Map<String, Object>>();     while (cs.moveToNext()) {       Map<String, Object> map = new HashMap<String, Object>();       map.put("name", cs.getString(0));       map.put("age", cs.getString(1));       lists.add(map);     }     SimpleAdapter simepl = new SimpleAdapter(MainActivity.this, lists,         R.layout.item, new String[] { "name", "age" }, new int[] {             R.id.item_txt1, R.id.item_txt2 });     return simepl;   }    @Override   public boolean onCreateOptionsMenu(Menu menu) {     // Inflate the menu; this adds items to the action bar if it is present.     getMenuInflater().inflate(R.menu.main, menu);     return true;   }  } 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   xmlns:tools="http://schemas.android.com/tools"   android:layout_width="match_parent"   android:layout_height="match_parent"   android:orientation="vertical"   tools:context=".MainActivity" >    <ScrollView     android:id="@+id/scr1"     android:layout_width="match_parent"     android:layout_height="wrap_content" >      <LinearLayout       android:layout_width="match_parent"       android:layout_height="wrap_content"       android:orientation="vertical" >        <Button         android:id="@+id/bt1"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:text="添加" />        <Button         android:id="@+id/bt2"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:text="删除" />        <Button         android:id="@+id/bt3"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:text="更改" />        <Button         android:id="@+id/bt4"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:text="查询" />        <EditText         android:id="@+id/ed1"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:hint="输入name条件进行增删改查" />        <EditText         android:id="@+id/ed2"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:hint="输age条件进行增删改查" />     </LinearLayout>   </ScrollView>    <ListView     android:id="@+id/list"     android:layout_width="match_parent"     android:layout_height="wrap_content" >   </ListView>  </LinearLayout> 

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   android:layout_width="match_parent"   android:layout_height="match_parent"   android:orientation="horizontal" >   <TextView      android:id="@+id/item_txt1"     android:layout_width="wrap_content"     android:layout_height="wrap_content"/>     <TextView      android:id="@+id/item_txt2"     android:layout_width="wrap_content"     android:layout_height="wrap_content"/>     </LinearLayout> 

//删除数据   @Override   public int delete(Uri uri, String selection, String[] selectionArgs) {     int number = 0;     if (uriMatcher.match(uri) == 1) {       // 根据条件删除数据,并获取删除的行数       number = mysqlite.getReadableDatabase().delete("user_info",           selection, selectionArgs);     }     // 通知数据已经改变     getContext().getContentResolver().notifyChange(uri, null);     return number;   } 

@Override protected void onCreate(Bundle savedInstanceState) {   super.onCreate(savedInstanceState);   setContentView(R.layout.activity_main);   // 为uri的数据改变注册监听器   getContentResolver().registerContentObserver(       Uri.parse("content://com.android.xiong.ConentProviderTestA.firstContentProvider/userinfo"), true,       new SmsObserver(new Handler())); } 

// 提供方自定义的ContentOberver监听器 private final class Observer extends ContentObserver {    public SmsObserver(Handler handler) {     super(handler);   }    @Override   public void onChange(boolean selfChange, Uri uri) {      // 查询发送邮箱中的短息(处于正在发送状态的短信放在发送箱)     Cursor cursor = getContentResolver().query(         Uri.parse("content://com.android.xiong.ConentProviderTestA.firstContentProvider/userinfo"), null, null, null, null);     }   }  }