版本:1.0
日期:2014.11.10 2014.11.11
版权:© 2014 kince 转载注明出处
一、概述
桌面抽屉之间的切换时Android用户经常触发的行为,好的交互会给用户一个舒适的体验。百度桌面默认是随机切换不同的动画,Android默认是一个大小和透明的渐变的动画,如下:
下面开始分析在Launcher2(KitKat)的源码里面是如何实现这种效果的。
二、下面列举相关的方法和变量
4082: interface LauncherTransitionable { View getContent(); void onLauncherTransitionPrepare(Launcher l, boolean animated, boolean toWorkspace); void onLauncherTransitionStart(Launcher l, boolean animated, boolean toWorkspace); void onLauncherTransitionStep(Launcher l, float t); void onLauncherTransitionEnd(Launcher l, boolean animated, boolean toWorkspace); } 2948: exitSpringLoadedDragMode() 2926: exitSpringLoadedDragModeDelayed() 2918: enterSpringLoadedDragMode() 2899: showAllApps() 2864: showWorkspace() 2860: showWorkspace() 2740: hideAppsCustomizeHelper() 2573: showAppsCustomizeHelper() 2498: dispatchOnLauncherTransitionPrepare() 2097: onClickAllAppsButton() 2048: onTouch() 2008: onClick() 1976: onBackPressed() 1456: onNewIntent 1273: mReceiver 749: onResume()
三、分析
首先从最直观的方式开始,就是Dock栏进入抽屉的按钮。点击它会从桌面到抽屉,进入抽屉后再按返回键会从抽屉到桌面。这个按钮在Launcher类中对应的变量是mAllAppsButton,因为Launcher类继承了View.OnClickListener, OnLongClickListener, LauncherModel.Callbacks,View.OnTouchListener这几个接口,所以点击事情需要由onClick(View v)方法来处理。在Launcher类的onClick(View v)方法中,
/** * Launches the intent referred by the clicked shortcut. * * @param v The view representing the clicked shortcut. */ public void onClick(View v) { // Make sure that rogue clicks don‘t get through while allapps is launching, or after the // view has detached (it‘s possible for this to happen if the view is removed mid touch). if (v.getWindowToken() == null) { return; } if (!mWorkspace .isFinishedSwitchingState()) { return; } Object tag = v.getTag(); if (tag instanceof ShortcutInfo) { // Open shortcut final Intent intent = ((ShortcutInfo) tag).intent; int[] pos = new int[2]; v.getLocationOnScreen(pos); intent.setSourceBounds( new Rect(pos[0], pos[1], pos[0] + v.getWidth(), pos[1] + v.getHeight())); boolean success = startActivitySafely(v, intent, tag); if (success && v instanceof BubbleTextView) { mWaitingForResume = (BubbleTextView) v; mWaitingForResume.setStayPressed(true); } } else if (tag instanceof FolderInfo) { if (v instanceof FolderIcon) { FolderIcon fi = (FolderIcon) v; handleFolderClick(fi); } } else if (v == mAllAppsButton ) { if (isAllAppsVisible()) { showWorkspace( true); } else { onClickAllAppsButton(v); } } }
从标注地方可以看出,首先对View进行一个判断,如果是mAllAppsButton则开始下面的判断。如果是在抽屉里面,则进入到桌面;如果不是抽屉,则调用onClickAllAppsButton(v)方法。而onClickAllAppsButton(v)方法就是调用showAllApps方法,顾名思义就是进入后抽屉显示所有的app。接着在抽屉里面,如果要返回桌面,按Back键的话会调用onKeyDown或者onBackPressed()方法。
@Override public boolean onKeyDown( int keyCode, KeyEvent event) { final int uniChar = event.getUnicodeChar(); final boolean handled = super.onKeyDown(keyCode, event); final boolean isKeyNotWhitespace = uniChar > 0 && !Character.isWhitespace(uniChar); if (!handled && acceptFilter() && isKeyNotWhitespace) { boolean gotKey = TextKeyListener.getInstance().onKeyDown( mWorkspace, mDefaultKeySsb, keyCode, event); if (gotKey && mDefaultKeySsb != null && mDefaultKeySsb.length() > 0) { // something usable has been typed - start a search // the typed text will be retrieved and cleared by // showSearchDialog() // If there are multiple keystrokes before the search dialog takes focus, // onSearchRequested() will be called for every keystroke, // but it is idempotent , so it‘s fine. return onSearchRequested(); } } // Eat the long press event so the keyboard doesn‘t come up. if (keyCode == KeyEvent.KEYCODE_MENU && event.isLongPress()) { return true ; } return handled; }
可以看到在onKeyDown方法中,没有任何关于进出抽屉或者桌面的方法。那么再来看一下onBackPressed()方法:
@Override public void onBackPressed() { if (isAllAppsVisible()) { showWorkspace( true); } else if (mWorkspace .getOpenFolder() != null) { Folder openFolder = mWorkspace.getOpenFolder(); if (openFolder.isEditingName()) { openFolder.dismissEditingName(); } else { closeFolder(); } } else { mWorkspace.exitWidgetResizeMode(); // Back button is a no-op here, but give at least some feedback for the button press mWorkspace.showOutlinesTemporarily(); } }
发现在这里处理了切换的过程。现在可以确定是显示桌面调用的是showWorkspace()方法,进入抽屉调用的是showAllApps()方法。在这两个方法中,又各自调用不同的方法实现各自的逻辑。
那么这两个方法都是在上面情况下调用的呢?先看showAllApps()方法。
launcher.java类:
1、onResume()
2、onClickAllAppsButton
再看一下showWorkspace()的情况,
1、onResume()
2、mReceiver()
3、onNewIntent()
4、startSearch()
5、startWallpaper()
6、onBackPressed()
7、onClick()
8、onTouch()
9、showWorkspace()
10、exitSpringLoadedDragModeDelayed()
可以发现showAllApps()方法只有被调用两次,而showWorkspace()有十次之多。这说明返回桌面的情形比返回抽屉的情况要多很多,而实际的使用情况也确实是这样的。
接着分别看一下showAllApps()和showWorkspace()各自的具体实现。
void showAllApps( boolean animated) { if (mState != State.WORKSPACE) return; showAppsCustomizeHelper(animated, false); mAppsCustomizeTabHost.requestFocus(); // Change the state *after* we‘ve called all the transition code mState = State. APPS_CUSTOMIZE; // Pause the auto-advance of widgets until we are out of AllApps mUserPresent = false ; updateRunning(); closeFolder(); // Send an accessibility event to announce the context change getWindow().getDecorView() .sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED); }
逐行分析下,第一行是一个判断,如果当前的状态不是在桌面,那么就退出这个方法。第二行代码就是进入抽屉的动画方法。
第三行代码是给抽屉界面焦点。第四行代码进入抽屉后更改当前的状态。之后就不细说了。重点还是showAppsCustomizeHelper(animated, false );这个方法,它就是实现进入抽屉动画的方法。来到这个方法,发现其上面有很长的注释:
/** * Things to test when changing the following seven functions. * - Home from workspace * - from center screen * - from other screens * - Home from all apps * - from center screen * - from other screens * - Back from all apps * - from center screen * - from other screens * - Launch app from workspace and quit * - with back * - with home * - Launch app from all apps and quit * - with back * - with home * - Go to a screen that‘s not the default, then all * apps, and launch and app, and go back * - with back * -with home * - On workspace, long press power and go back * - with back * - with home * - On all apps, long press power and go back * - with back * - with home * - On workspace, power off * - On all apps, power off * - Launch an app and turn off the screen while in that app * - Go back with home key * - Go back with back key TODO: make this not go to workspace * - From all apps * - From workspace * - Enter and exit car mode (becuase it causes an extra configuration changed) * - From all apps * - From the center workspace * - From another workspace */
注释下面是showAppsCustomizeHelper()和hideAppsCustomizeHelper()两个方法,顾名思义hideAppsCustomizeHelper就是离开抽屉的动画实现方法,这两个方法是相对立的。
/** * Zoom the camera out from the workspace to reveal ‘toView‘. * Assumes that the view to show is anchored at either the very top or very bottom * of the screen. */ private void showAppsCustomizeHelper(final boolean animated, final boolean springLoaded) { if (mStateAnimation != null) { mStateAnimation.setDuration(0); mStateAnimation.cancel(); mStateAnimation = null ; } final Resources res = getResources(); final int duration = res.getInteger(R.integer.config_appsCustomizeZoomInTime ); final int fadeDuration = res.getInteger(R.integer.config_appsCustomizeFadeInTime ); final float scale = (float) res.getInteger(R.integer.config_appsCustomizeZoomScaleFactor ); final View fromView = mWorkspace ; final AppsCustomizeTabHost toView = mAppsCustomizeTabHost; final int startDelay = res.getInteger(R.integer.config_workspaceAppsCustomizeAnimationStagger ); setPivotsForZoom(toView, scale); // Shrink workspaces away if going to AppsCustomize from workspace Animator workspaceAnim = mWorkspace.getChangeStateAnimation(Workspace.State.SMALL, animated); if (animated) { toView.setScaleX(scale); toView.setScaleY(scale); final LauncherViewPropertyAnimator scaleAnim = new LauncherViewPropertyAnimator(toView); scaleAnim. scaleX(1f).scaleY(1f). setDuration(duration). setInterpolator( new Workspace.ZoomOutInterpolator()); toView.setVisibility(View. VISIBLE); toView.setAlpha(0f); final ObjectAnimator alphaAnim = LauncherAnimUtils . ofFloat(toView, "alpha", 0f, 1f) .setDuration(fadeDuration); alphaAnim.setInterpolator( new DecelerateInterpolator(1.5f)); alphaAnim.addUpdateListener( new AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { if (animation == null) { throw new RuntimeException("animation is null" ); } float t = (Float) animation.getAnimatedValue(); dispatchOnLauncherTransitionStep(fromView, t); dispatchOnLauncherTransitionStep(toView, t); } }); // toView should appear right at the end of the workspace shrink // animation mStateAnimation = LauncherAnimUtils.createAnimatorSet(); mStateAnimation.play(scaleAnim).after(startDelay); mStateAnimation.play(alphaAnim).after(startDelay); mStateAnimation.addListener(new AnimatorListenerAdapter() { boolean animationCancelled = false; @Override public void onAnimationStart(Animator animation) { updateWallpaperVisibility( true); // Prepare the position toView.setTranslationX(0.0f); toView.setTranslationY(0.0f); toView.setVisibility(View. VISIBLE); toView.bringToFront(); } @Override public void onAnimationEnd(Animator animation) { dispatchOnLauncherTransitionEnd(fromView, animated, false); dispatchOnLauncherTransitionEnd(toView, animated, false); if (mWorkspace != null && !springLoaded && !LauncherApplication.isScreenLarge()) { // Hide the workspace scrollbar mWorkspace.hideScrollingIndicator(true); hideDockDivider(); } if (!animationCancelled ) { updateWallpaperVisibility( false); } // Hide the search bar if (mSearchDropTargetBar != null) { mSearchDropTargetBar.hideSearchBar(false); } } @Override public void onAnimationCancel(Animator animation) { animationCancelled = true ; } }); if (workspaceAnim != null) { mStateAnimation.play(workspaceAnim); } boolean delayAnim = false; dispatchOnLauncherTransitionPrepare(fromView, animated, false); dispatchOnLauncherTransitionPrepare(toView, animated, false); // If any of the objects being animated haven‘t been measured/laid out // yet, delay the animation until we get a layout pass if ((((LauncherTransitionable) toView).getContent().getMeasuredWidth() == 0) || ( mWorkspace.getMeasuredWidth() == 0) || (toView.getMeasuredWidth() == 0)) { delayAnim = true; } final AnimatorSet stateAnimation = mStateAnimation; final Runnable startAnimRunnable = new Runnable() { public void run() { // Check that mStateAnimation hasn‘t changed while // we waited for a layout/draw pass if (mStateAnimation != stateAnimation) return; setPivotsForZoom(toView, scale); dispatchOnLauncherTransitionStart(fromView, animated, false); dispatchOnLauncherTransitionStart(toView, animated, false); LauncherAnimUtils.startAnimationAfterNextDraw( mStateAnimation, toView); } }; if (delayAnim) { final ViewTreeObserver observer = toView.getViewTreeObserver(); observer.addOnGlobalLayoutListener( new OnGlobalLayoutListener() { public void onGlobalLayout() { startAnimRunnable.run(); toView.getViewTreeObserver().removeOnGlobalLayoutListener(this); } }); } else { startAnimRunnable.run(); } } else { toView.setTranslationX(0.0f); toView.setTranslationY(0.0f); toView.setScaleX(1.0f); toView.setScaleY(1.0f); toView.setVisibility(View. VISIBLE); toView.bringToFront(); if (!springLoaded && !LauncherApplication.isScreenLarge()) { // Hide the workspace scrollbar mWorkspace.hideScrollingIndicator(true); hideDockDivider(); // Hide the search bar if (mSearchDropTargetBar != null) { mSearchDropTargetBar.hideSearchBar(false); } } dispatchOnLauncherTransitionPrepare(fromView, animated, false); dispatchOnLauncherTransitionStart(fromView, animated, false); dispatchOnLauncherTransitionEnd(fromView, animated, false); dispatchOnLauncherTransitionPrepare(toView, animated, false); dispatchOnLauncherTransitionStart(toView, animated, false); dispatchOnLauncherTransitionEnd(toView, animated, false); updateWallpaperVisibility( false); } }
变量mStateAnimation的类型是AnimatorSet,是专门负责上述两个方法里面的动画执行。变量duration、fadeDuration、scale分别是进入抽屉动画的伸缩的时间、透明度改变的时间以及伸缩的大小。从下面两行代码可以看出
final View fromView = mWorkspace; final AppsCustomizeTabHost toView = mAppsCustomizeTabHost ;
fromView就是桌面,而toView就是抽屉。startDelay是动画之前的准备时间。
setPivotsForZoom(toView, scale);方法是对View进行一个缩放,scale是缩放的参数。
workspaceAnim是桌面消失的动画,先不去看具体实现。如果有动画需求进入if判断,在这里有一个scaleAnim和alphaAnim,这就是抽屉出现的动画,从代码
mStateAnimation = LauncherAnimUtils.createAnimatorSet(); mStateAnimation.play(scaleAnim).after(startDelay); mStateAnimation.play(alphaAnim).after(startDelay);
可以看出二者同时执行。接着是mStateAnimation动画的回调接口,具体逻辑不再分析。然后如果workspaceAnim不为空的话,就执行说明消失的动画。再看delayAnim变量,这是用来判断是否需要延迟动画执行。如果需要的话就监听View树是绘制,绘制完毕之后再执行动画;否则执行进入抽屉的动画。还有一个重要的地方是在在上面的方法中出现了
dispatchOnLauncherTransitionPrepare(fromView, animated, false); dispatchOnLauncherTransitionStart(fromView, animated, false); dispatchOnLauncherTransitionEnd(fromView, animated, false);
等方法。其实这是在Launcher类中定义的接口里面的方法,具体如下:
interface LauncherTransitionable { View getContent(); void onLauncherTransitionPrepare(Launcher l, boolean animated, boolean toWorkspace); void onLauncherTransitionStart(Launcher l, boolean animated, boolean toWorkspace); void onLauncherTransitionStep(Launcher l, float t); void onLauncherTransitionEnd(Launcher l, boolean animated, boolean toWorkspace); }
分别在Workspace、AppsCustomizePagedView、AppsCustomizeTabHost、PagedView中继承这个接口。最后回过头看一下桌面消失动画的实现,它是在Workspace类里面处理的。
Animator getChangeStateAnimation (final SizeState state, boolean animated, int delay) { Log.i(TAG, "getChangeStateAnimation"); if (mSizeState == state) { return null ; } // Initialize animation arrays for the first time if necessary initAnimationArrays(); AnimatorSet anim = animated ? LauncherAnimUtils.createAnimatorSet() : null; // Stop any scrolling, move to the current page right away setCurrentPage(getNextPage()); final boolean isEditViewMode = isEditViewMode(state); final SizeState oldState = mSizeState ; final boolean oldStateIsNormal = (oldState == SizeState.NORMAL); final boolean oldStateIsSpringLoaded = (oldState == SizeState.SPRING_LOADED ); final boolean oldStateIsSmall = (oldState == SizeState.SMALL); mSizeState = state; final boolean stateIsNormal = (state == SizeState.NORMAL); final boolean stateIsSpringLoaded = (state == SizeState.SPRING_LOADED ); final boolean stateIsSmall = (state == SizeState.SMALL); float finalScaleFactor = 1.0f; float finalBackgroundAlpha = (stateIsSpringLoaded || isEditViewMode) ? 1.0f: 0f; float translationX = 0; float translationY = 0; boolean zoomIn = true; if (state != SizeState.NORMAL) { if (isEditViewMode) { finalScaleFactor = getCellLayoutScale(state); } else { finalScaleFactor = mSpringLoadedShrinkFactor- (state == SizeState.SMALL ? 0.1f : 0); } finalScaleFactor = mSpringLoadedShrinkFactor - (stateIsSmall ? 0.1f : 0); setPageSpacing(mSpringLoadedPageSpacing); if (oldStateIsNormal && stateIsSmall) { zoomIn = false; setLayoutScale(finalScaleFactor); updateChildrenLayersEnabled( false); } else { finalBackgroundAlpha = 1.0f; setLayoutScale(finalScaleFactor); } } else { setPageSpacing(mOriginalPageSpacing); setLayoutScale(1.0f); } final int duration; if (isEditViewMode) { duration = getResources().getInteger(R.integer.config_overviewTransitionTime ); } else if (zoomIn) { duration = getResources().getInteger(R.integer.config_workspaceUnshrinkTime ); } else { duration = getResources().getInteger(R.integer.config_appsCustomizeWorkspaceShrinkTime ); } for (int i = 0; i < getChildCount(); i++) { final CellLayout cl = (CellLayout) getChildAt(i); float finalAlpha = (!mWorkspaceFadeInAdjacentScreens || stateIsSpringLoaded ||(i == mCurrentPage)) ? 1f : 0f; float currentAlpha = cl.getShortcutsAndWidgets().getAlpha(); float initialAlpha = currentAlpha; // Determine the pages alpha during the state transition if ((oldStateIsSmall && stateIsNormal) || (oldStateIsNormal && stateIsSmall)) { // To/from workspace - only show the current page unless the transition is not // animated and the animation end callback below doesn‘t run; // or, if we‘re in spring-loaded mode if (i == mCurrentPage || !animated || oldStateIsSpringLoaded) { finalAlpha = 1f; } else { initialAlpha = 0f; finalAlpha = 0f; } } mOldAlphas[i] = initialAlpha; mNewAlphas[i] = finalAlpha; if (animated) { mOldTranslationXs[i] = cl.getTranslationX(); mOldTranslationYs[i] = cl.getTranslationY(); mOldScaleXs[i] = cl.getScaleX(); mOldScaleYs[i] = cl.getScaleY(); mOldBackgroundAlphas[i] = cl.getBackgroundAlpha(); mNewTranslationXs[i] = translationX; mNewTranslationYs[i] = translationY; mNewScaleXs[i] = finalScaleFactor; mNewScaleYs[i] = finalScaleFactor; mNewBackgroundAlphas[i] = finalBackgroundAlpha; } else { cl.setTranslationX(translationX); cl.setTranslationY(translationY); cl.setScaleX(finalScaleFactor); cl.setScaleY(finalScaleFactor); cl.setBackgroundAlpha(finalBackgroundAlpha); cl.setShortcutAndWidgetAlpha(finalAlpha); } cl.isEditViewMode(isEditViewMode); } if (animated) { for (int index = 0; index < getChildCount(); index++) { final int i = index; final CellLayout cl = (CellLayout) getChildAt(i); float currentAlpha = cl.getShortcutsAndWidgets().getAlpha(); if (mOldAlphas [i] == 0 && mNewAlphas[i] == 0) { cl.setTranslationX(mNewTranslationXs [i]); cl.setTranslationY(mNewTranslationYs [i]); cl.setScaleX( mNewScaleXs[i]); cl.setScaleY( mNewScaleYs[i]); cl.setBackgroundAlpha(mNewBackgroundAlphas [i]); cl.setShortcutAndWidgetAlpha(mNewAlphas [i]); cl.setRotationY( mNewRotationYs[i]); } else { LauncherViewPropertyAnimator a = new LauncherViewPropertyAnimator(cl); a.translationX( mNewTranslationXs[i]) .translationY(mNewTranslationYs [i]) .scaleX( mNewScaleXs[i]) .scaleY( mNewScaleYs[i]) .setDuration(duration) .setInterpolator(mZoomInInterpolator ); anim.play(a); if (mOldAlphas [i] != mNewAlphas [i] || currentAlpha != mNewAlphas [i]) { LauncherViewPropertyAnimator alphaAnim = new LauncherViewPropertyAnimator(cl.getShortcutsAndWidgets()); alphaAnim.alpha( mNewAlphas[i]) .setDuration(duration) .setInterpolator(mZoomInInterpolator ); anim.play(alphaAnim); } if (mOldBackgroundAlphas [i] != 0 || mNewBackgroundAlphas[i] != 0) { ValueAnimator bgAnim = LauncherAnimUtils.ofFloat(cl, 0f, 1f).setDuration(duration); bgAnim.setInterpolator(mZoomInInterpolator ); bgAnim.addUpdateListener( new LauncherAnimatorUpdateListener() { public void onAnimationUpdate(float a, float b) { cl.setBackgroundAlpha( a * mOldBackgroundAlphas[i] + b * mNewBackgroundAlphas[i]); } }); anim.play(bgAnim); } } } anim.setStartDelay(delay); } if (stateIsSpringLoaded) { // Right now we‘re covered by Apps Customize // Show the background gradient immediately, so the gradient will // be showing once AppsCustomize disappears animateBackgroundGradient(getResources().getInteger( R.integer.config_appsCustomizeSpringLoadedBgAlpha ) / 100f, false); } else { // Fade the background gradient away animateBackgroundGradient(0f, true); } return anim; }
在说明方法之前先说一下,Launcher2和Launcher3桌面消失动画的区别。Launcher2进入抽屉后是一个黑色的背景,没有壁纸显示效果,而Launcher3可以看到壁纸。所以getChangeStateAnimation 方法也是有一定区别的。关于这个方法大体可以分为三个部分,一是变量初始赋值阶段,二是动画设置阶段,三是动画返回阶段。重点是第二个动画设置阶段,因为桌面的消失、出现都会调用这个方法。同样的关于这个动画最主要的部分还是伸缩和透明度的变化,理论上应该是这样的,桌面消失时开始变小、透明度逐渐不可见;桌面出现时开始变大、透明度逐渐可见。
不过从这个方法的实现来看,其性能消耗比较大。它是用一个for循环来遍历Workspace的CellLayout的个数,也就是有几个桌面。然后再对每个CellLayout进行一个动画效果。亲测在低端机器上比如联想s868t是非常卡顿的。
hideAppsCustomizeHelper()的实现就不再赘述,和showAppsCustomizeHelper()实现机制都是一样的。那么最后总结一下,从桌面进入抽屉调用
hideAppsCustomizeHelper()方法,这个方法实现进入抽屉的动画效果,具体说就是对抽屉这个View进行一个动画。在这方法里面还有一个桌面消失的动画getChangeStateAnimation ,在这个动画执行完毕后才会执行进入抽屉的动画。然后从抽屉返回桌面正好是相反的流程。现在很多桌面进入抽屉都会有其他的动画效果,比如反转、上下等效果,其实就是对以上三个方法进行修改添加就可以了。