刪除表中數據的兩種方法（delete刪）

1.通過點擊按鈕來執行刪除表中數據。（數據庫和表的創建不在詳細介紹，請自動閱讀數據庫和表的創建）

第一種方法：直接使用SQL來操作數據庫，調用execSQL(sql)語句

public class MainActivity extends AppCompatActivity {
    private Button mDeleteButton;
    private MySqliteHelper mMySqliteHelper;
    private SQLiteDatabase db;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mMySqliteHelper = DbManger.getIntance(MainActivity.this);
        mDeleteButton = (Button) findViewById(R.id.delete_btn);
        //點擊按鈕刪除數據
        mDeleteButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                db = mMySqliteHelper.getWritableDatabase();
                String sql = "delete from "+Constant.TABLE_NAME+" where "+Constant.ID+" = 2 ";
                db.execSQL(sql);
                db.close();
            }
        });
    }
}

第二種方法：使用android API封裝好的刪除數據的操作

public class MainActivity extends AppCompatActivity {
    private Button mDeleteButton;
    private MySqliteHelper mMySqliteHelper;
    private SQLiteDatabase db;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mMySqliteHelper = DbManger.getIntance(MainActivity.this);
        mDeleteButton = (Button) findViewById(R.id.delete_btn);
        //點擊按鈕刪除數據
        mDeleteButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                db = mMySqliteHelper.getWritableDatabase();
                db.delete(Constant.TABLE_NAME,Constant.ID+" = ?",new String[]{"3"});
                db.close();
            }
        });
    }
}