contentprovider 实例

Provider端

public class PersonProvider extends ContentProvider {
 
    //用来存放所有合法的Uri的容器
    private static UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);
    //保存一些合法的uri
    // content://com.atguigu.l09_provider.personprovider/person 不根据id操作
    // content://com.atguigu.l09_provider.personprovider/person/3 根据id操作
    static {
        matcher.addURI("com.atguigu.l09_provider.personprovider", "/person", 1);
        matcher.addURI("com.atguigu.l09_provider.personprovider", "/person/#", 2);  //#匹配任意数字
    }
    private DBHelper dbHelper;
    public PersonProvider() {
        Log.e("TAG", "PersonProvider()");
    }
    @Override
    public boolean onCreate() {
        Log.e("TAG", "PersonProvider onCreate()");
        dbHelper = new DBHelper(getContext());
 
        return false;
    }
 
    /**
     * content://com.atguigu.l09_provider.personprovider/person 不根据id查询
     * content://com.atguigu.l09_provider.personprovider/person/3 根据id查询
     */
    @Override
    public Cursor query(Uri uri, String[] projection, String selection,
            String[] selectionArgs, String sortOrder) {
        Log.e("TAG", "PersonProvider query()");
 
        //得到连接对象
        SQLiteDatabase database = dbHelper.getReadableDatabase();
 
        //1.匹配uri, 返回code
        int code = matcher.match(uri);
        //如果合法, 进行查询
        if(code==1) {//不根据id查询
            Cursor cursor = database.query("person", projection, selection, selectionArgs, null, null, null);
            return cursor;
        } else if(code==2) {//根据id查询
            //得到id
            long id = ContentUris.parseId(uri);
            //查询
            Cursor cursor = database.query("person", projection, "_id=?", new String[]{id+""}, null, null, null);
            return cursor;
        } else {//如果不合法, 抛出异常
            throw new RuntimeException("查询的uri不合法");
        }
    }
 
    /**
     * content://com.atguigu.l09_provider.personprovider/person 插入
     * content://com.atguigu.l09_provider.personprovider/person/3 根据id插入(没有)
     */
    @Override
    public Uri insert(Uri uri, ContentValues values) {
        Log.e("TAG", "PersonProvider insert()");
        //得到连接对象
        SQLiteDatabase database = dbHelper.getReadableDatabase();
        //匹配uri, 返回code
        int code = matcher.match(uri);
        //如果合法, 进行插入
        if(code==1) {
            long id = database.insert("person", null, values);
            //将id添加到uri中
            uri = ContentUris.withAppendedId(uri, id);
            database.close();
            return uri;
        } else {
            //如果不合法, 抛出异常
            database.close();
            throw new RuntimeException("插入的uri不合法");
        }
    }
 
    /**
     * content://com.atguigu.l09_provider.personprovider/person 不根据id删除
     * content://com.atguigu.l09_provider.personprovider/person/3 根据id删除
     */
    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        Log.e("TAG", "PersonProvider delete()");
        //得到连接对象
        SQLiteDatabase database = dbHelper.getReadableDatabase();
        //匹配uri, 返回code
        int code = matcher.match(uri);
        int deleteCount = -1;
        //如果合法, 进行删除
        if(code==1) {
            deleteCount = database.delete("person", selection, selectionArgs);
        } else if(code==2) {
            long id = ContentUris.parseId(uri);
            deleteCount = database.delete("person", "_id="+id, null);
        } else {
            //如果不合法, 抛出异常
            database.close();
            throw new RuntimeException("删除的uri不合法");
        }
 
        database.close();
        return deleteCount;
    }
 
    /**
     * content://com.atguigu.l09_provider.personprovider/person 不根据id更新
     * content://com.atguigu.l09_provider.personprovider/person/3 根据id更新
     */
    @Override
    public int update(Uri uri, ContentValues values, String selection,
            String[] selectionArgs) {
        Log.e("TAG", "PersonProvider update()");
        //得到连接对象
        SQLiteDatabase database = dbHelper.getReadableDatabase();
        //匹配uri, 返回code
        int code = matcher.match(uri);
        int updateCount = -1;
        //如果合法, 进行更新
        if(code==1) {
            updateCount = database.update("person", values, selection, selectionArgs);
        } else if(code==2) {
            long id = ContentUris.parseId(uri);
            updateCount = database.update("person", values, "_id="+id, null);
        } else {
            //如果不合法, 抛出异常
            database.close();
            throw new RuntimeException("更新的uri不合法");
        }
 
        database.close();
        return updateCount;
    }
 
    @Override
    public String getType(Uri uri) {
        // TODO Auto-generated method stub
        return null;
    }
}

  <provider android:name="com.atguigu.l09_provider.PersonProvider"
            android:authorities="com.atguigu.l09_provider.personprovider"
            android:exported="true"/>
        <!-- exported : 是否可以让其它应用访问 -->

Resolver端

/*
     * 通过ContentResolver调用ContentProvider插入一条记录
     */
    public void insert(View v) {
        //1. 得到ContentResolver对象
        ContentResolver resolver = getContentResolver();
        //2. 调用其insert
        Uri uri = Uri.parse("content://com.atguigu.l09_provider.personprovider/person");
        //uri = Uri.parse("content://com.atguigu.l09_provider.personprovider/person/3");
        ContentValues values = new ContentValues();
        values.put("name", "JACK");
        uri = resolver.insert(uri, values);
 
        Toast.makeText(this, uri.toString(), 1).show();
    }
 
    /*
     * 通过ContentResolver调用ContentProvider更新一条记录
     */
    public void update(View v) {
        //1. 得到ContentResolver对象
        ContentResolver resolver = getContentResolver();
        //2. 执行update
        Uri uri = Uri.parse("content://com.atguigu.l09_provider.personprovider/person/2");
        ContentValues values = new ContentValues();
        values.put("name", "JACK2");
        int updateCount = resolver.update(uri, values, null, null);
 
        Toast.makeText(this, "updateCount="+updateCount, 1).show();
    }
 
    /*
     * 通过ContentResolver调用ContentProvider删除一条记录
     */
    public void delete(View v) {
        //1. 得到ContentResolver对象
        ContentResolver resolver = getContentResolver();
        //2. 执行delete
        Uri uri = Uri.parse("content://com.atguigu.l09_provider.personprovider/person/2");
        int deleteCount = resolver.delete(uri, null, null);
        Toast.makeText(this, "deleteCount="+deleteCount, 1).show();
    }
 
    /*
     * 通过ContentResolver调用ContentProvider查询所有记录
     */
    public void query(View v) {
        //1. 得到ContentResolver对象
        ContentResolver resolver = getContentResolver();
        //2. 调用其query, 得到cursor
        Uri uri = Uri.parse("content://com.atguigu.l09_provider.personprovider/person/1");
        uri = Uri.parse("content://com.atguigu.l09_provider.personprovider/person");
        Cursor cusor = resolver.query(uri, null, null, null, null);
        //3. 取出cursor中的数据, 并显示
        while(cusor.moveToNext()) {
            int id = cusor.getInt(0);
            String name = cusor.getString(1);
            Toast.makeText(this, id+" : "+name, 1).show();
        }
        cusor.close();
    }