如何在android手机的后退按钮上停止/取消runnable？

public class MainActivity extends AppCompatActivity {
    private Handler mHandler;
    private Runnable mRunnable;

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

        mHandler = new Handler();
        mRunnable = new Runnable() {
            @Override
            public void run() {
                // 在这里执行你的任务逻辑
            }
        };
    }

    @Override
    public void onBackPressed() {
        // 停止或取消Runnable
        mHandler.removeCallbacks(mRunnable);
        super.onBackPressed();
    }
}