Android中View點擊事件傳遞(一)

原創

木小_可ing

2020-02-21 09:29

android 中點擊事件傳遞設計到的方法有dispatchTouchEvent，OnTouchEvent，OnTouch，onClick。其中除了onClick方法外，其他方法都有三種常用的手勢：

ACTION_DOWN:手指點擊屏幕時調用。
ACTION_UP:手指離開屏幕時調用。

ACTION_MOVE：手指在屏幕上移動特定的距離時調用。

並且其他三種方法都有返回值，根據返回值的不同往下執行的結果也不相同。

根據這個問題來做個實驗：

1.創建自定義textView，其中重寫dispatchTouchEvent,OnTouchEvent方法，並且根據三種手勢打出日誌：

public class MTextView extends TextView {

    public MTextView(Context context) {
        super(context);
    }

    public MTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MTextView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {

        switch (event.getAction()){
            case MotionEvent.ACTION_DOWN:
                System.out.println("MTextView dispatchTouchEvent ACTION_DOWN");
                break;
            case MotionEvent.ACTION_UP:
                System.out.println("MTextView dispatchTouchEvent ACTION_UP");
                break;
            case MotionEvent.ACTION_MOVE:
                System.out.println("MTextView dispatchTouchEvent ACTION_MOVE");
                break;
            case MotionEvent.ACTION_CANCEL:
                System.out.println("MTextView dispatchTouchEvent ACTION_CANCEL");
                break;
        }
        return super.dispatchTouchEvent(event);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()){
            case MotionEvent.ACTION_DOWN:
                System.out.println("MTextView onTouchEvent ACTION_DOWN");
                break;
            case MotionEvent.ACTION_UP:
                System.out.println("MTextView onTouchEvent ACTION_UP");
                break;
            case MotionEvent.ACTION_MOVE:
                System.out.println("MTextView onTouchEvent ACTION_MOVE");
                break;
            case MotionEvent.ACTION_CANCEL:
                System.out.println("MTextView onTouchEvent ACTION_CANCEL");
                break;
        }
        return super.onTouchEvent(event);
    }
}

2.在MainActivity中調用自定義textView，並且重寫 dispatchTouchEvent,OnTouchEvent，Ontouch，onClick方法：

public class MainActivity extends AppCompatActivity implements View.OnTouchListener,View.OnClickListener{
    private TextView text;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        text= (TextView) findViewById(R.id.text);
        text.setOnTouchListener(this);
        text.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.text:
                System.out.println("MainActivity  onClick");
                break;
        }
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        switch (v.getId()){
            case R.id.text:
                switch (event.getAction()){
                    case MotionEvent.ACTION_DOWN:
                        System.out.println("MainActivity onTouch ACTION_DOWN");
                        break;
                    case MotionEvent.ACTION_UP:
                        System.out.println("MainActivity onTouch ACTION_UP");
                        break;
                    case  MotionEvent.ACTION_MOVE:
                        System.out.println("MainActivity onTouch ACTION_MOVE");
                        break;
                }
                break;
        }
        return false;
    }
    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {

        switch (event.getAction()){
            case MotionEvent.ACTION_DOWN:
                System.out.println("MainActivity dispatchTouchEvent ACTION_DOWN");
                break;
            case MotionEvent.ACTION_UP:
                System.out.println("MainActivity dispatchTouchEvent ACTION_UP");
                break;
            case MotionEvent.ACTION_MOVE:
                System.out.println("MainActivity dispatchTouchEvent ACTION_MOVE");
                break;
            case MotionEvent.ACTION_CANCEL:
                System.out.println("MainActivity dispatchTouchEvent ACTION_CANCEL");
                break;
        }
        return super.dispatchTouchEvent(event);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()){
            case MotionEvent.ACTION_DOWN:
                System.out.println("MainActivity onTouchEvent ACTION_DOWN");
                break;
            case MotionEvent.ACTION_UP:
                System.out.println("MainActivity onTouchEvent ACTION_UP");
                break;
            case MotionEvent.ACTION_MOVE:
                System.out.println("MainActivity onTouchEvent ACTION_MOVE");
                break;
            case MotionEvent.ACTION_CANCEL:
                System.out.println("MainActivity onTouchEvent ACTION_CANCEL");
                break;
        }
        return super.onTouchEvent(event);
    }

}

（1）按照以上代碼運行則運行的順序是：

System.out: MainActivity dispatchTouchEvent ACTION_DOWN
System.out: MTextView dispatchTouchEvent ACTION_DOWN
System.out: MainActivity onTouch ACTION_DOWN
System.out: MTextView onTouchEvent ACTION_DOWN
System.out: MainActivity dispatchTouchEvent ACTION_MOVE
System.out: MTextView dispatchTouchEvent ACTION_MOVE
System.out: MainActivity onTouch ACTION_MOVE
System.out: MTextView onTouchEvent ACTION_MOVE
System.out: MainActivity dispatchTouchEvent ACTION_UP
System.out: MTextView dispatchTouchEvent ACTION_UP
System.out: MainActivity onTouch ACTION_UP
System.out: MTextView onTouchEvent ACTION_UP
System.out: MainActivity onClick
可以看出來執行的順序按方法排dispatchTouchEvent—>ontouch—>ontouchevent—>onClick,
按照類的順序來看 MainActivity—>MTextView

```````接下的放在下一篇