View Groupイベント配信メカニズムソースコード解析(一)View編

Viewイベント処理メカニズムソース分析

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/rootView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/buttonView"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:text="button" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_marginTop="10dp"
        android:background="@color/colorPrimaryDark"
        android:text="image" />

</LinearLayout>

		button.setOnClickListener(new View.OnClickListener() {
     
            @Override
            public void onClick(View v) {
     
                Log.e("normally", "button onClick");
            }
        });

        button.setOnTouchListener(new View.OnTouchListener() {
     
            @Override
            public boolean onTouch(View v, MotionEvent event) {
     
                Log.e("normally", "button onTouch: " + getAction(event.getAction()) + "--clickable:" + button.isClickable());

                return false;
            }
        });

/com.oman.dispatch E/normally: button onTouch:  DOWN--clickable:true
/com.oman.dispatch E/normally: button onTouch:  MOVE--clickable:true
/com.oman.dispatch E/normally: button onTouch:  UP--clickable:true
/com.oman.dispatch E/normally: button onClick

/com.oman.dispatch E/normally: button onTouch:  DOWN--clickable:true
/com.oman.dispatch E/normally: button onTouch:  MOVE--clickable:true
/com.oman.dispatch E/normally: button onTouch:  UP--clickable:true

	public boolean dispatchTouchEvent(MotionEvent event) {
     
        ...
        boolean result = false;
        ...
        if (onFilterTouchEventForSecurity(event)) {
     
            ...
            ListenerInfo li = mListenerInfo;
            // 1 
            if (li != null && li.mOnTouchListener != null
                    && (mViewFlags & ENABLED_MASK) == ENABLED
                    && li.mOnTouchListener.onTouch(this, event)) {
     
                result = true;
            }
			// 2
            if (!result && onTouchEvent(event)) {
     
                result = true;
            }
        }
        // 3
        return result;
    }

public void setOnTouchListener(OnTouchListener l) {
       
    getListenerInfo().mOnTouchListener = l;
}

View.onTouchEvent

	public boolean onTouchEvent(MotionEvent event) {
     
        final float x = event.getX();
        final float y = event.getY();
        final int viewFlags = mViewFlags;
        final int action = event.getAction();
		...
		// 1
        if (clickable || (viewFlags & TOOLTIP) == TOOLTIP) {
     
            switch (action) {
     
                case MotionEvent.ACTION_UP:
                   
                    boolean prepressed = (mPrivateFlags & PFLAG_PREPRESSED) != 0;
                    if ((mPrivateFlags & PFLAG_PRESSED) != 0 || prepressed) {
     
                        
                        if (!mHasPerformedLongPress && !mIgnoreNextUpEvent) {
     
                            // This is a tap, so remove the longpress check
                            removeLongPressCallback();

                            // Only perform take click actions if we were in the pressed state
                            if (!focusTaken) {
     
                                // Use a Runnable and post this rather than calling
                                // performClick directly. This lets other visual state
                                // of the view update before click actions start.
                                if (mPerformClick == null) {
     
                                    mPerformClick = new PerformClick();
                                }
                                if (!post(mPerformClick)) {
     
                                	// 2
                                    performClickInternal();
                                }
                            }
                        }

                        ...
                    }
                    mIgnoreNextUpEvent = false;
                    break;

                case MotionEvent.ACTION_DOWN:
                    ...
                    break;

                case MotionEvent.ACTION_CANCEL:
                    ...
                    break;

                case MotionEvent.ACTION_MOVE:
                    ...
                    break;
            }

            return true;
        }

        return false;
    }

	private boolean performClickInternal() {
     
        return performClick();
    }
	
	public boolean performClick() {
     
        ...
        final boolean result;
        final ListenerInfo li = mListenerInfo;
        if (li != null && li.mOnClickListener != null) {
     
            playSoundEffect(SoundEffectConstants.CLICK);
            // 1
            li.mOnClickListener.onClick(this);
            result = true;
        } else {
     
            result = false;
        }
        return result;
    }

	public void setOnClickListener(@Nullable OnClickListener l) {
     
        if (!isClickable()) {
     
            setClickable(true);
        }
        getListenerInfo().mOnClickListener = l;
    }

ImageViewのテスト状況

	imageView.setOnTouchListener(new View.OnTouchListener() {
     
        @Override
        public boolean onTouch(View v, MotionEvent event) {
     
            Log.e("normally", "image onTouch: " + getAction(event.getAction()) + "--clickable:" + imageView.isClickable());
            return false;
        }
    });

/com.oman.dispatch E/normally: image onTouch:  DOWN--clickable:false

/com.oman.dispatch E/normally: image onTouch:  DOWN--clickable:false
/com.oman.dispatch E/normally: image onTouch:  MOVE--clickable:false
/com.oman.dispatch E/normally: image onTouch:  UP--clickable:false

	imageView.setOnTouchListener(new View.OnTouchListener() {
     
        @Override
        public boolean onTouch(View v, MotionEvent event) {
     
            Log.e("normally", "image onTouch: " + getAction(event.getAction()) + "--clickable:" + imageView.isClickable());
            return false;
        }
        });
    imageView.setOnClickListener(new View.OnClickListener() {
     
        @Override
        public void onClick(View v) {
     
            Log.e("normally", "image onClick");
        }
    });

/com.oman.dispatch E/normally: image onTouch:  DOWN--clickable:true
/com.oman.dispatch E/normally: image onTouch:  MOVE--clickable:true
/com.oman.dispatch E/normally: image onTouch:  UP--clickable:true
/com.oman.dispatch E/normally: image onClick

/com.oman.dispatch E/normally: image onTouch:  DOWN--clickable:true
/com.oman.dispatch E/normally: image onTouch:  MOVE--clickable:true
/com.oman.dispatch E/normally: image onTouch:  UP--clickable:true

	public void setOnClickListener(@Nullable OnClickListener l) {
     
        if (!isClickable()) {
     
            // 1
            setClickable(true);
        }
        getListenerInfo().mOnClickListener = l;
    }

小結