這幾天遇到點關於Android的觸摸事件相關的,還跟onClick有關,暫且記下:
LinearLayout分別設置了onTouchListener,onClickListener,onLongClickListener及onTouchEvent回調
1、在屏幕上觸摸之後基本的執行流程如下:
onTouch,action=0
onTouchEvent,action=0
onTouch,action=2
onTouchEvent,action=2
onTouch,action=2
onTouchEvent,action=2
onTouch,action=1
onTouchEvent,action=1
onClick
也就是先說onTouchListener是最先被觸發的,然後是本身的onTouchEvent回調;當最後的up事件發生並被onTouchEvent處理後纔會觸發onClickListener。
2、把onTouchEvent回調中的super.onTouchEvent去除,直接返回true;則流程如下:
onTouch,action=0
onTouchEvent,action=0
onTouch,action=2
onTouchEvent,action=2
onTouch,action=2
onTouchEvent,action=2
onTouch,action=1
onTouchEvent,action=1
可以看到onClickListener永遠無法被觸發,也側面說明了對onClick的觸發是在onTouchEvent回調中來實現的。
3、長按屏幕,流程如下:
onTouch,action=0
onTouchEvent,action=0
onTouch,action=2
onTouchEvent,action=2
onTouch,action=2
onTouchEvent,action=2
onLongClick
onTouch,action=2
onTouchEvent,action=2
onTouch,action=2
onTouchEvent,action=2
onTouch,action=1
onTouchEvent,action=1
onClick
當長按的時候,無需到up就會觸發onLongClick的響應,但之後也會繼續觸發onClick的響應。
4、但如果在onLongClick中返回true,則流程如下,即只在中間觸發了onLongClick,之後會繼續響應touch,但當up的時候就不會再觸發onClick
onTouch,action=0
onTouchEvent,action=0
onTouch,action=2
onTouchEvent,action=2
onTouch,action=2
onTouchEvent,action=2
onLongClick
onTouch,action=2
onTouchEvent,action=2
onTouch,action=2
onTouchEvent,action=2
onTouch,action=1
onTouchEvent,action=1
測試代碼如下:
- public class MainActivity extends Activity {
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- FrameLayout frame = (FrameLayout)findViewById(R.id.container);
- LinearLayoutTest line = new LinearLayoutTest(this);
- line.setOnClickListener(new ClickListener());
- line.setOnLongClickListener(new LongClickListener());
- line.setOnTouchListener(new TouchListener());
- line.setLongClickable(true);
- frame.addView(line);
- }
- public class ClickListener implements OnClickListener {
- @Override
- public void onClick(View v) {
- Log.e("test","onClick");
- }
- }
- public class LongClickListener implements OnLongClickListener{
- @Override
- public boolean onLongClick(View v) {
- Log.e("test","onLongClick");
- return true;
- }
- }
- public class TouchListener implements OnTouchListener{
- @Override
- public boolean onTouch(View v, MotionEvent event) {
- Log.e("test","onTouch,action="+event.getAction());
- return false;
- }
- }
- }
- public class LinearLayoutTest extends LinearLayout{
- public LinearLayoutTest(Context context) {
- super(context);
- }
- @Override
- public boolean onTouchEvent(MotionEvent event) {
- Log.e("test","onTouchEvent,action="+event.getAction());
- return super.onTouchEvent(event);
- }
- }