如何处理android自定义视图中的后退按钮？

public class CustomView extends View {
    private Activity mActivity;

    public CustomView(Context context) {
        super(context);
        mActivity = (Activity) context;
    }
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    if (event.getAction() == MotionEvent.ACTION_DOWN) {
        int x = (int) event.getX();
        int y = (int) event.getY();
        if (x < backButtonWidth && y < backButtonHeight) {
            mActivity.onBackPressed(); // 执行后退操作
            return true;
        }
    }
    return super.onTouchEvent(event);
}

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        CustomView customView = new CustomView(this);
        LinearLayout layout = findViewById(R.id.layout);
        layout.addView(customView);
    }
}