android canvas 点击事件,android Canvas 画板 和 OnTouch 事件

public class MainActivity extends Activity {

ImageView image;

Button bt_save, bt_clear;

int downX, downY, moveX, moveY;

Canvas canvas;

Bitmap bitmap;

Paint paint;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

initView();

}

public void initView() {

image = (ImageView) findViewById(R.id.image);

bt_clear = (Button) findViewById(R.id.bt_clear);

bt_save = (Button) findViewById(R.id.bt_save);

image.setOnTouchListener(new MyOnTouchListener());

}

class MyOnTouchListener implements OnTouchListener {

@Override

public boolean onTouch(View v, MotionEvent event) {

switch (event.getAction()) {

case Motio