編輯:關於Android編程
本文背景:前些天用到了之前寫的自定義圖片文字復合控件,在給他設置監聽時遇到了麻煩。雖然最後解決了問題,但發現在不重寫LinearLayout的onInterceptTouchEvent時,子ImageView、子TextView、父Linearlayout三者不同的屬性配置(android:clickable android:focuseable)會造成自定義控件onClick監聽失敗、或成功。復寫了父Linearlayout 的onInterceptTouchEvent時,監聽不受子圖片、子文字的屬性影響。為知其所以然,深入研究android的事件傳遞機制,記錄於此。
/** * Pass the touch screen motion event down to the target view, or this * view if it is the target. * * @param event The motion event to be dispatched. * @return True if the event was handled by the view, false otherwise. */ public boolean dispatchTouchEvent(MotionEvent event) { if (mInputEventConsistencyVerifier != null) { mInputEventConsistencyVerifier.onTouchEvent(event, 0); } if (onFilterTouchEventForSecurity(event)) { //noinspection SimplifiableIfStatement ListenerInfo li = mListenerInfo; if (li != null && li.mOnTouchListener != null && (mViewFlags & ENABLED_MASK) == ENABLED && li.mOnTouchListener.onTouch(this, event)) { return true; } if (onTouchEvent(event)) { return true; } } if (mInputEventConsistencyVerifier != null) { mInputEventConsistencyVerifier.onUnhandledEvent(event, 0); } return false; }找到這個判斷: if (li != null && li.mOnTouchListener != null && (mViewFlags & ENABLED_MASK) == ENABLED
if (onTouchEvent(event)) { return true; }onTouchEvent的源碼比較多,貼最重要的:
if (!mHasPerformedLongPress) { // 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)) { performClick(); } } }可以看到有個performClick(),它的源碼裡有這麼一句 li.mOnClickListener.onClick(this);
public boolean performClick() { sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED); ListenerInfo li = mListenerInfo; if (li != null && li.mOnClickListener != null) { playSoundEffect(SoundEffectConstants.CLICK); li.mOnClickListener.onClick(this); return true; } return false; }
package org.yanzi.ui; import android.content.Context; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.widget.Button; public class TestButton extends Button { private final static String tag = "yan"; public TestButton(Context context, AttributeSet attrs) { super(context, attrs); // TODO Auto-generated constructor stub } @Override public boolean onTouchEvent(MotionEvent event) { // TODO Auto-generated method stub switch(event.getAction()){ case MotionEvent.ACTION_DOWN: Log.i(tag, "TestButton-onTouchEvent-ACTION_DOWN..."); break; case MotionEvent.ACTION_UP: Log.i(tag, "TestButton-onTouchEvent-ACTION_UP..."); break; default:break; } return super.onTouchEvent(event); } @Override public boolean dispatchTouchEvent(MotionEvent event) { // TODO Auto-generated method stub switch(event.getAction()){ case MotionEvent.ACTION_DOWN: Log.i(tag, "TestButton-dispatchTouchEvent-ACTION_DOWN..."); break; case MotionEvent.ACTION_UP: Log.i(tag, "TestButton-dispatchTouchEvent-ACTION_UP..."); break; default:break; } return super.dispatchTouchEvent(event); } }
testBtn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub Log.i(tag, "testBtn---onClick..."); } }); testBtn.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { // TODO Auto-generated method stub switch(event.getAction()){ case MotionEvent.ACTION_DOWN: Log.i(tag, "testBtn-onTouch-ACTION_DOWN..."); break; case MotionEvent.ACTION_UP: Log.i(tag, "testBtn-onTouch-ACTION_UP..."); break; default:break; } return false; } });
@Override public boolean dispatchTouchEvent(MotionEvent ev) { // TODO Auto-generated method stub switch(ev.getAction()){ case MotionEvent.ACTION_DOWN: Log.i(tag, "MainActivity-dispatchTouchEvent-ACTION_DOWN..."); break; case MotionEvent.ACTION_UP: Log.i(tag, "MainActivity-dispatchTouchEvent-ACTION_UP..."); break; default:break; } return super.dispatchTouchEvent(ev); } @Override public boolean onTouchEvent(MotionEvent event) { // TODO Auto-generated method stub switch(event.getAction()){ case MotionEvent.ACTION_DOWN: Log.i(tag, "MainActivity-onTouchEvent-ACTION_DOWN..."); break; case MotionEvent.ACTION_UP: Log.i(tag, "MainActivity-onTouchEvent-ACTION_UP..."); break; default:break; } return super.onTouchEvent(event); }
testBtn.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { // TODO Auto-generated method stub switch(event.getAction()){ case MotionEvent.ACTION_DOWN: Log.i(tag, "testBtn-onTouch-ACTION_DOWN..."); break; case MotionEvent.ACTION_UP: Log.i(tag, "testBtn-onTouch-ACTION_UP..."); break; default:break; } return true; } });
public boolean dispatchTouchEvent(MotionEvent ev) { if (mInputEventConsistencyVerifier != null) { mInputEventConsistencyVerifier.onTouchEvent(ev, 1); } boolean handled = false; if (onFilterTouchEventForSecurity(ev)) { final int action = ev.getAction(); final int actionMasked = action & MotionEvent.ACTION_MASK; // Handle an initial down. if (actionMasked == MotionEvent.ACTION_DOWN) { // Throw away all previous state when starting a new touch gesture. // The framework may have dropped the up or cancel event for the previous gesture // due to an app switch, ANR, or some other state change. cancelAndClearTouchTargets(ev); resetTouchState(); } // Check for interception. final boolean intercepted; if (actionMasked == MotionEvent.ACTION_DOWN || mFirstTouchTarget != null) { final boolean disallowIntercept = (mGroupFlags & FLAG_DISALLOW_INTERCEPT) != 0; if (!disallowIntercept) { intercepted = onInterceptTouchEvent(ev); ev.setAction(action); // restore action in case it was changed } else { intercepted = false; } } else { // There are no touch targets and this action is not an initial down // so this view group continues to intercept touches. intercepted = true; } // Check for cancelation. final boolean canceled = resetCancelNextUpFlag(this) || actionMasked == MotionEvent.ACTION_CANCEL; // Update list of touch targets for pointer down, if needed. final boolean split = (mGroupFlags & FLAG_SPLIT_MOTION_EVENTS) != 0; TouchTarget newTouchTarget = null; boolean alreadyDispatchedToNewTouchTarget = false; if (!canceled && !intercepted) { if (actionMasked == MotionEvent.ACTION_DOWN || (split && actionMasked == MotionEvent.ACTION_POINTER_DOWN) || actionMasked == MotionEvent.ACTION_HOVER_MOVE) { final int actionIndex = ev.getActionIndex(); // always 0 for down final int idBitsToAssign = split ? 1 << ev.getPointerId(actionIndex) : TouchTarget.ALL_POINTER_IDS; // Clean up earlier touch targets for this pointer id in case they // have become out of sync. removePointersFromTouchTargets(idBitsToAssign); final int childrenCount = mChildrenCount; if (childrenCount != 0) { // Find a child that can receive the event. // Scan children from front to back. final View[] children = mChildren; final float x = ev.getX(actionIndex); final float y = ev.getY(actionIndex); final boolean customOrder = isChildrenDrawingOrderEnabled(); for (int i = childrenCount - 1; i >= 0; i--) { final int childIndex = customOrder ? getChildDrawingOrder(childrenCount, i) : i; final View child = children[childIndex]; if (!canViewReceivePointerEvents(child) || !isTransformedTouchPointInView(x, y, child, null)) { continue; } newTouchTarget = getTouchTarget(child); if (newTouchTarget != null) { // Child is already receiving touch within its bounds. // Give it the new pointer in addition to the ones it is handling. newTouchTarget.pointerIdBits |= idBitsToAssign; break; } resetCancelNextUpFlag(child); if (dispatchTransformedTouchEvent(ev, false, child, idBitsToAssign)) { // Child wants to receive touch within its bounds. mLastTouchDownTime = ev.getDownTime(); mLastTouchDownIndex = childIndex; mLastTouchDownX = ev.getX(); mLastTouchDownY = ev.getY(); newTouchTarget = addTouchTarget(child, idBitsToAssign); alreadyDispatchedToNewTouchTarget = true; break; } } } if (newTouchTarget == null && mFirstTouchTarget != null) { // Did not find a child to receive the event. // Assign the pointer to the least recently added target. newTouchTarget = mFirstTouchTarget; while (newTouchTarget.next != null) { newTouchTarget = newTouchTarget.next; } newTouchTarget.pointerIdBits |= idBitsToAssign; } } } // Dispatch to touch targets. if (mFirstTouchTarget == null) { // No touch targets so treat this as an ordinary view. handled = dispatchTransformedTouchEvent(ev, canceled, null, TouchTarget.ALL_POINTER_IDS); } else { // Dispatch to touch targets, excluding the new touch target if we already // dispatched to it. Cancel touch targets if necessary. TouchTarget predecessor = null; TouchTarget target = mFirstTouchTarget; while (target != null) { final TouchTarget next = target.next; if (alreadyDispatchedToNewTouchTarget && target == newTouchTarget) { handled = true; } else { final boolean cancelChild = resetCancelNextUpFlag(target.child) || intercepted; if (dispatchTransformedTouchEvent(ev, cancelChild, target.child, target.pointerIdBits)) { handled = true; } if (cancelChild) { if (predecessor == null) { mFirstTouchTarget = next; } else { predecessor.next = next; } target.recycle(); target = next; continue; } } predecessor = target; target = next; } } // Update list of touch targets for pointer up or cancel, if needed. if (canceled || actionMasked == MotionEvent.ACTION_UP || actionMasked == MotionEvent.ACTION_HOVER_MOVE) { resetTouchState(); } else if (split && actionMasked == MotionEvent.ACTION_POINTER_UP) { final int actionIndex = ev.getActionIndex(); final int idBitsToRemove = 1 << ev.getPointerId(actionIndex); removePointersFromTouchTargets(idBitsToRemove); } } if (!handled && mInputEventConsistencyVerifier != null) { mInputEventConsistencyVerifier.onUnhandledEvent(ev, 1); } return handled; }
public boolean onInterceptTouchEvent(MotionEvent ev) { return false; }
package org.yanzi.ui; import android.content.Context; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.widget.LinearLayout; public class TestLinearLayout extends LinearLayout{ private final static String tag = "yan"; public TestLinearLayout(Context context, AttributeSet attrs) { super(context, attrs); // TODO Auto-generated constructor stub } @Override public boolean dispatchTouchEvent(MotionEvent ev) { // TODO Auto-generated method stub switch(ev.getAction()){ case MotionEvent.ACTION_DOWN: Log.i(tag, "TestLinearLayout-dispatchTouchEvent-ACTION_DOWN..."); break; case MotionEvent.ACTION_UP: Log.i(tag, "TestLinearLayout-dispatchTouchEvent-ACTION_UP..."); break; default:break; } return super.dispatchTouchEvent(ev); } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { // TODO Auto-generated method stub switch(ev.getAction()){ case MotionEvent.ACTION_DOWN: Log.i(tag, "TestLinearLayout-onInterceptTouchEvent-ACTION_DOWN..."); break; case MotionEvent.ACTION_UP: Log.i(tag, "TestLinearLayout-onInterceptTouchEvent-ACTION_UP..."); break; default:break; } return super.onInterceptTouchEvent(ev); } @Override public boolean onTouchEvent(MotionEvent event) { // TODO Auto-generated method stub switch(event.getAction()){ case MotionEvent.ACTION_DOWN: Log.i(tag, "TestLinearLayout-onTouchEvent-ACTION_DOWN..."); break; case MotionEvent.ACTION_UP: Log.i(tag, "TestLinearLayout-onTouchEvent-ACTION_UP..."); break; default:break; } return super.onTouchEvent(event); } }布局文件改成:
testLinelayout = (TestLinearLayout)findViewById(R.id.linearlayout_test); testLinelayout.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { // TODO Auto-generated method stub switch(event.getAction()){ case MotionEvent.ACTION_DOWN: Log.i(tag, "testLinelayout-onTouch-ACTION_DOWN..."); break; case MotionEvent.ACTION_UP: Log.i(tag, "testLinelayout-onTouch-ACTION_UP..."); break; default:break; } return false; } }); testLinelayout.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub Log.i(tag, "testLinelayout---onClick..."); } });
本文實例講述了Android仿百度谷歌搜索自動提示框AutoCompleteTextView簡單應用。分享給大家供大家參考,具體如下:現在我們上網幾乎都會用百度或者谷歌搜
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