private Button btnWrite;    private Button btnRead;    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        btnRead = (Button) findViewById(R.id.btnRead);        btnWrite = (Button) findViewById(R.id.btnWrite);        btnRead.setOnClickListener(new ButtonListener());        btnWrite.setOnClickListener(new ButtonListener());    }    private class ButtonListener implements OnClickListener {        public void onClick(View v) {            switch (v.getId()) {            case R.id.btnRead:                Toast.makeText(MainActivity.this, "读取", Toast.LENGTH_SHORT)                        .show();                break;            case R.id.btnWrite:                Toast.makeText(MainActivity.this, "写入", Toast.LENGTH_SHORT)                        .show();                break;            default:                break;            }        }    }