ContentProvider的简单范例

第一步数据库的建立

public class MyDatabaseHelp extends SQLiteOpenHelper {
    private static final String DB_NAME = "person.db";
    private static final int version = 1;

    public MyDatabaseHelp(@Nullable Context context) {
        super(context,DB_NAME,null,version);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String sql = "create table person(" +
                "id integer primary key," +
                "name varchar(20) not null," +
                "age Integer," +
                "birthday date)";
        db.execSQL(sql);
    }

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

    }
}

创建ContentProvider

public class MyContentProvider extends ContentProvider {
    private MyDatabaseHelp dbHelp;
    private SQLiteDatabase db;

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        // Implement this to handle requests to delete one or more rows.
        throw new UnsupportedOperationException("Not yet implemented");
    }

    @Override
    public String getType(Uri uri) {
        // TODO: Implement this to handle requests for the MIME type of the data
        // at the given URI.
        throw new UnsupportedOperationException("Not yet implemented");
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        Log.e("zhy","数据插入 Uri == " + uri + "   contentValues == " + values);
        long person = db.insert("person", null, values);
        Log.e("zhy","数据 id == " + person);
        Uri uri1 = ContentUris.withAppendedId(uri, person);
        return uri1;
    }

    @Override
    public boolean onCreate() {
        dbHelp = new MyDatabaseHelp(getContext());
        db = dbHelp.getWritableDatabase();
        return false;
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection,
                        String[] selectionArgs, String sortOrder) {
        Log.e("zhy","数据查询");
        Cursor cursor = db.query("person", null, null, null, null, null, null);
        return cursor;
    }

    @Override
    public int update(Uri uri, ContentValues values, String selection,
                      String[] selectionArgs) {
        // TODO: Implement this to handle requests to update one or more rows.
        throw new UnsupportedOperationException("Not yet implemented");
    }

使用ContentResolver 进行增删改查

switch (v.getId()) {
            case R.id.btn_insert:
                ContentValues contentValues = new ContentValues();
                contentValues.put("name","haige");
                contentValues.put("age","13");
                resolver.insert(uri,contentValues);
                break;
            case R.id.btn_query:
                Cursor query = resolver.query(uri, null, null, null, null);
                Log.e("zhy","数据数量 == " + query.getCount());
                while(query.moveToNext()) {
                    //for (int i = 0;i < query.getColumnCount();i++) {
                        Log.e("zhy","数据 == " + query.getString(1));
                    //}
                }
                query.close();
                break;
        }