ContentProvider简单使用

ContentProvider简单使用

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        MyOpenHelper myOpenHelper = new MyOpenHelper(this);
        SQLiteDatabase db = myOpenHelper.getReadableDatabase();
        Cursor cursor = db.query("info", null, null, null, null, null, null);
        if (cursor!=null && cursor.getCount()>0){
            while (cursor.moveToNext()){
                String name = cursor.getString(1);
                int money = cursor.getInt(2);
                System.out.println("----"+name+money);


            }
        }
    }
}

public class MyDBProvider extends ContentProvider {
    private MyOpenHelper myOpenHelper;
    private static final int QUERY_SUCCESS=1;
    private static final int INSERT_SUCCESS=2;
    private static final int UPDATE_SUCCESS=3;
    private static final int DELETE_SUCCESS=4;



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

        static {
            sUriMatcher.addURI("lijinpeng","query",QUERY_SUCCESS);
            sUriMatcher.addURI("lijinpeng","insert",INSERT_SUCCESS);
            sUriMatcher.addURI("lijinpeng","update",UPDATE_SUCCESS);
            sUriMatcher.addURI("lijinpeng","delete",DELETE_SUCCESS);

        }



    @Override
    public boolean onCreate() {
        myOpenHelper = new MyOpenHelper(getContext());
        return false;
    }


    @Override
    public Cursor query( Uri uri,  String[] projection, String selection, String[] selectionArgs,  String sortOrder) {
        int match = sUriMatcher.match(uri);
        switch (match){
            case QUERY_SUCCESS :
                SQLiteDatabase db = myOpenHelper.getReadableDatabase();
                Cursor cursor = db.query("info", projection, selection, selectionArgs, null, null, sortOrder);
                return cursor;

                default:
                    return null;
        }

    }


    @Override
    public String getType( Uri uri) {
        return null;
    }


    /*match不匹配会有异常*/
    @Override
    public Uri insert( Uri uri,  ContentValues values) {
        int match = sUriMatcher.match(uri);
        switch (match){
            case INSERT_SUCCESS:
                SQLiteDatabase db = myOpenHelper.getReadableDatabase();
                long insert = db.insert("info",null,values);
                db.close();
                return Uri.parse("insert ="+insert) ;
                default:
                    throw new IllegalArgumentException("wrong my man");

        }
    }
    @Override
    public int delete( Uri uri,  String selection,  String[] selectionArgs) {
        int match = sUriMatcher.match(uri);
        switch (match) {
            case DELETE_SUCCESS:
                SQLiteDatabase db = myOpenHelper.getReadableDatabase();
                int delete = db.delete("info", selection, selectionArgs);
                db.close();
                return delete;
            default:
                return  -1;
        }
    }

    @Override
    public int update(Uri uri, ContentValues values,String selection, String[] selectionArgs) {
        int match = sUriMatcher.match(uri);
        switch (match) {
            case UPDATE_SUCCESS:
                SQLiteDatabase db = myOpenHelper.getReadableDatabase();
                int update = db.update("info", values, selection, selectionArgs);
                db.close();
                return update;
            default:
                return -1;
        }

    }
}

public class MyOpenHelper extends SQLiteOpenHelper {
    public MyOpenHelper( Context context) {
        super(context, "MyDb.db", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        db.execSQL("create table info (_id integer primary key autoincrement,name varchar(20),money integer)");
        db.execSQL("insert into info(name,money) values (?,?)",new String[]{"kevin","2000"});
        db.execSQL("insert into info(name,money) values (?,?)",new String[]{"wx","10000"});
    }

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

    }
}

读

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        /*String path= "/data/data/com.example.dbprovider_51/databases/MyDb.db";
        SQLiteDatabase db = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READWRITE);
        Cursor cursor = db.query("info", null, null, null, null, null, null);
        if (cursor!=null && cursor.getCount()>0){
            while (cursor.moveToNext()){
                String name = cursor.getString(1);
                int money = cursor.getInt(2);
                System.out.println("--------name = "+name+"/money = "+money);
不好的方法

            }
        }*/

    }

    public void query(View view) {
        Uri uri = Uri.parse("content://lijinpeng/query");
        ContentResolver resolver = getContentResolver();
        Cursor cursor = resolver.query(uri, null, null, null, null);
        if (cursor != null && cursor.getCount() > 0) {
            while (cursor.moveToNext()) {
                String name = cursor.getString(1);
                int money = cursor.getInt(2);
                System.out.println("--------name = " + name + "/money = " + money);
            }
        }
    }
    public void insert(View view) {
        Uri uri = Uri.parse("content://lijinpeng/insert");
        ContentResolver resolver = getContentResolver();
        ContentValues values = new ContentValues();
        values.put("name","ppp");
        values.put("money","111");
        Uri insert = resolver.insert(uri, values);
        if (insert !=null){
            Toast.makeText(this, insert.toString(), Toast.LENGTH_SHORT).show();
        }
    }
    public void updata(View view) {
        Uri uri = Uri.parse("content://lijinpeng/update");
        ContentResolver resolver = getContentResolver();
        ContentValues values = new ContentValues();
        values.put("money","999");
        int update = resolver.update(uri,values,"name =?",new String[]{"ppp"});
            Toast.makeText(this,"--------update"+update, Toast.LENGTH_SHORT).show();

    }

    public void delete(View view) {
        Uri uri = Uri.parse("content://lijinpeng/delete");
        ContentResolver resolver = getContentResolver();
        int delete = resolver.delete(uri, null, null);
            Toast.makeText(this,"--------delete"+delete, Toast.LENGTH_SHORT).show();


    }
}