ContentProvider使用示例

1、MyContentProvider

public class MyContentProviderextends ContentProvider {

private static final StringTAG ="MyContentProvider";

    private Contextcontext;

    private SQLiteDatabasesqLiteDatabase;

    public static final StringAUTHORITY ="com.examp.mycontentprovider.MyContentProvider";

    public static final int PROVIDER_CODE =0;

    private static final UriMatcheruriMatcher =new UriMatcher(UriMatcher.NO_MATCH);

    static {

            uriMatcher.addURI(AUTHORITY, MyDBHelper.TABLE_NAME, PROVIDER_CODE);

    }

    public MyContentProvider() {

    }

    /**

    * 通过uri匹配表名

    *

    * @param uri

    * @return

    */

    private StringgetTableName(Uri uri) {

        String tableName =null;

        switch (uriMatcher.match(uri)) {

                case PROVIDER_CODE:

                tableName = MyDBHelper.TABLE_NAME;

                break;

        }

        return tableName;

    }

@Override

    public boolean onCreate() {

            init();

    return false;

    }

    private void init() {

        context = getContext();

        sqLiteDatabase =new MyDBHelper(context).getWritableDatabase();

    }

@Nullable

@Override

    public Cursorquery(@NonNull Uri uri, @Nullable String[] projection, @Nullable String selection, @Nullable String[] selectionArgs, @Nullable String sortOrder) {

        String tableName = getTableName(uri);

        if (tableName ==null) {

            Log.e(TAG, "query: 未匹配到uri");

            throw new IllegalArgumentException("Unsupported URI:" + uri);

        }

        return sqLiteDatabase.query(tableName, projection, selection, selectionArgs, null, null,             sortOrder, null);

    }

@Nullable

@Override

    public StringgetType(@NonNull Uri uri) {

        return null;

    }

    @Nullable

    @Override

    public Uriinsert(@NonNull Uri uri, @Nullable ContentValues values) {

            String tableName = getTableName(uri);

            if (tableName ==null) {

            Log.e(TAG, "insert: 未匹配到uri");

            throw new IllegalArgumentException("Unsupported URI:" + uri);

            }

            sqLiteDatabase.insert(tableName, null, values);

            context.getContentResolver().notifyChange(uri, null);

            Log.d(TAG, "insert: 添加成功");

            return uri;

    }

    @Override

    public int delete(@NonNull Uri uri, @Nullable String selection, @Nullable String[] selectionArgs) {

            String tableName = getTableName(uri);

            if (tableName ==null) {

            Log.e(TAG, "delete: 未匹配到uri");

            throw new IllegalArgumentException("Unsupported URI:" + uri);

            }

            int count =sqLiteDatabase.delete(tableName, selection, selectionArgs);

            if (count >0) {

            context.getContentResolver().notifyChange(uri, null);

        }

            Log.d(TAG, "delete: 删除成功");

            Log.d(TAG, "delete: count=" + count);

        return count;

    }

    @Override

    public int update(@NonNull Uri uri, @Nullable ContentValues values, @Nullable String selection, @Nullable String[] selectionArgs) {

            String tableName = getTableName(uri);

            if (tableName ==null) {

                throw new IllegalArgumentException("Unsupported URI:" + uri);

            }

            int row =sqLiteDatabase.update(tableName, values, selection, selectionArgs);

            if (row >0) {

                context.getContentResolver().notifyChange(uri, null);

        }

        return row;

    }

}


2、MyDBHelper

public class MyDBHelperextends SQLiteOpenHelper {

/**

* 库名

*/

    private static final StringDBNAME ="provider.db";

    /**

* 表明 测试用

*/

    public static final StringTABLE_NAME ="provider_data";

    /**

* 版本号

*/

    private static final int VERSION =1;

    /**

    * 建表的sql语句

    */

    private static final StringSQL ="create table " +TABLE_NAME +"(id integer primary key Autoincrement,name text)";

    private Contextcontext;

    public MyDBHelper(Context context) {

        super(context, DBNAME, null, VERSION);

        this.context = context;

    }

@Override

    public void onCreate(SQLiteDatabase db) {

        db.execSQL(SQL);

        Toast.makeText(context, "建表成功", Toast.LENGTH_SHORT).show();

        Log.d("MyContentProvider", "onCreate: 建表成功");

    }

    @Override

    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

}


3、在MainActivity中使用

public class MainActivityextends AppCompatActivityimplements View.OnClickListener {

private static final StringTAG ="MyContentProvider";

    @Override

    protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        initView();

    }

private void initView() {

        Button bt_init = findViewById(R.id.bt_init);

        bt_init.setOnClickListener(this);

        Button bt_add = findViewById(R.id.bt_add);

        bt_add.setOnClickListener(this);

        Button bt_delete = findViewById(R.id.bt_delete);

        bt_delete.setOnClickListener(this);

        Button bt_update = findViewById(R.id.bt_update);

        bt_update.setOnClickListener(this);

        Button bt_query = findViewById(R.id.bt_query);

        bt_query.setOnClickListener(this);

    }

@Override

    public void onClick(View v) {

        switch (v.getId()) {

            case R.id.bt_init:

                    init();

                break;

            case R.id.bt_add:

                    toAdd();

                break;

            case R.id.bt_delete:

                toDelete();

                break;

            case R.id.bt_update:

                toUpdate();

            break;

            case R.id.bt_query:

                toQuery();

            break;

        }

}

    private void init() {

        getContentResolver().delete(nameUri, null, null);

    }

    private UrinameUri = Uri.parse("content://com.examp.mycontentprovider.MyContentProvider/provider_data");

    private void toAdd() {

        ContentValues contentValues =new ContentValues();

        contentValues.put("name", "水货");

        getContentResolver().insert(nameUri, contentValues);

    }

    private void toDelete() {

            getContentResolver().delete(nameUri, "name=?", new String[]{"水货"});

    }

    private void toUpdate() {

        ContentValues contentValues =new ContentValues();

        contentValues.put("name", "太阳");

        getContentResolver().update(nameUri, contentValues, "id=?", new String[]{"21"});

    }

private void toQuery() {

            Cursor nameCursor = getContentResolver().query(nameUri, new String[]{"id", "name"}, null, null, null);

            if (nameCursor !=null) {

                while (nameCursor.moveToNext()) {

                Log.e(TAG, "id:" + nameCursor.getInt(nameCursor.getColumnIndex("id"))

                +" name:" + nameCursor.getString(nameCursor.getColumnIndex("name")));

            }

                Log.d(TAG, "toQuery: 查询成功");

                nameCursor.close();

        }

    }

}


4、activity_main.xml

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:gravity="center_horizontal"

    android:orientation="vertical"

    tools:context=".MainActivity">

        android:id="@+id/bt_init"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="初始化" />

        android:id="@+id/bt_add"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="添加" />

        android:id="@+id/bt_delete"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="删除" />

        android:id="@+id/bt_update"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="更新" />

        android:id="@+id/bt_query"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="查询" />


5、manifest

    package="com.examp.mycontentprovider">

        android:allowBackup="true"

        android:icon="@mipmap/ic_launcher"

        android:label="@string/app_name"

        android:roundIcon="@mipmap/ic_launcher_round"

        android:supportsRtl="true"

        android:theme="@style/AppTheme">

       

               

               

            android:name=".MyContentProvider"

            android:authorities="com.examp.mycontentprovider.MyContentProvider"

            android:exported="true"/>

你可能感兴趣的:(ContentProvider使用示例)