Android 12源码单手模式

Android 12平台上现在支持单手模式了，此功能也是第一次出现在AOSP的源码中，也是Gg仿 IOS 15 单手模式，来追一追，看看其工作原理。

1.设置应用功能开关界面

com.android.settings.gestures.OneHandedEnablePreferenceController.java
com.android.settings.gestures.OneHandedMainSwitchPreferenceController.java
com.android.settings.gestures.OneHandedSettingsUtils.java

由以上三个文件可以看到：

(1)单手模式的系统开关为：ro.support_one_handed_mode
(2)单手模式显示在系统手势界面
(3)单手模式开关逻辑代码为：

    /*** Sets one-handed mode enable or disable flag to Settings provider.** @param context App context* @param enable  enable or disable one-handed mode.*/public static void setOneHandedModeEnabled(Context context, boolean enable) {Settings.Secure.putIntForUser(context.getContentResolver(),Settings.Secure.ONE_HANDED_MODE_ENABLED, enable ? ON : OFF, sCurrentUserId);}

2.Launcher3 单手模式手势启动过程

com.android.quickstep.inputconsumers.OneHandedModeInputConsumer.java
com.android.quickstep.SystemUiProxy.java

OneHandedModeInputConsumer类是手势导航处理的类，对于此类的功能描述如下：

 * Touch consumer for handling gesture event to launch one handed* One handed gestural in quickstep only active on NO_BUTTON, TWO_BUTTONS, and portrait mode* 触摸消费者处理手势事件以启动单手模式* Quickstep 中的单手手势处理仅在 NO_BUTTON、TWO_BUTTONS 和手机纵向模式下有效。

开启单手模式功能，需要从屏幕底部边缘向下滑动可以开启手势导航，其启动逻辑为:

    SystemUiProxy.INSTANCE.get(mContext).startOneHandedMode();public void startOneHandedMode() {if (mOneHanded != null) {try {mOneHanded.startOneHanded();} catch (RemoteException e) {Log.w(TAG, "Failed call startOneHandedMode", e);}}}

3.framework单手模式服务处理过程

(1)单手模式推出进入控制器

com.android.wm.shell.onehanded.IOneHanded.aidl
com.android.wm.shell.onehanded.OneHandedController.java
com.android.wm.shell.onehanded.OneHandedDisplayAreaOrganizer.java
com.android.wm.shell.onehanded.OneHandedAnimationController.java
com.android.wm.shell.onehanded.OneHandedTouchHandler.java
com.android.wm.shell.onehanded.OneHandedSurfaceTransactionHelper.java

    @VisibleForTestingvoid startOneHanded() {if (isLockedDisabled() || mKeyguardShowing) {Slog.d(TAG, "Temporary lock disabled");return;}if (!mDisplayAreaOrganizer.isReady()) {// Must wait until DisplayAreaOrganizer is ready for transitioning.mMainExecutor.executeDelayed(this::startOneHanded, DISPLAY_AREA_READY_RETRY_MS);return;}if (mState.isTransitioning() || mState.isInOneHanded()) {return;}final int currentRotation = mDisplayAreaOrganizer.getDisplayLayout().rotation();if (currentRotation != Surface.ROTATION_0 && currentRotation != Surface.ROTATION_180) {Slog.w(TAG, "One handed mode only support portrait mode");return;}mState.setState(STATE_ENTERING);final int yOffSet = Math.round(mDisplayAreaOrganizer.getDisplayLayout().height() * mOffSetFraction);mOneHandedAccessibilityUtil.announcementForScreenReader(mOneHandedAccessibilityUtil.getOneHandedStartDescription());mBackgroundPanelOrganizer.onStart();mDisplayAreaOrganizer.scheduleOffset(0, yOffSet);mTimeoutHandler.resetTimer();mOneHandedUiEventLogger.writeEvent(OneHandedUiEventLogger.EVENT_ONE_HANDED_TRIGGER_GESTURE_IN);}

由以上可以看到，设备锁定/锁屏/横屏是不允许进入单手模式的。进入单手模式时屏幕会有Y轴方向的偏移，偏移百分比为mOffSetFraction，mOffSetFraction的值获取是从 R.fraction.config_one_handed_offset获取的:

frameworks/base/libs/WindowManager/Shell/res/values/config.xml

    <fraction name="config_one_handed_offset">40%</fraction>

接着上面说，单手模式会对的显示做偏移：

/*** Offset the windows by a given offset on Y-axis, triggered also from screen rotation.* Directly perform manipulation/offset on the leash.*/public void scheduleOffset(int xOffset, int yOffset) {final float fromPos = mLastVisualOffset;final int direction = yOffset > 0? TRANSITION_DIRECTION_TRIGGER: TRANSITION_DIRECTION_EXIT;mDisplayAreaTokenMap.forEach((token, leash) -> {animateWindows(token, leash, fromPos, yOffset, direction,mEnterExitAnimationDurationMs);});mLastVisualOffset = yOffset;}private void animateWindows(WindowContainerToken token, SurfaceControl leash, float fromPos,float toPos, @OneHandedAnimationController.TransitionDirection int direction,int durationMs) {final OneHandedAnimationController.OneHandedTransitionAnimator animator =mAnimationController.getAnimator(token, leash, fromPos, toPos,mLastVisualDisplayBounds);if (animator != null) {animator.setTransitionDirection(direction).addOneHandedAnimationCallback(mOneHandedAnimationCallback).addOneHandedAnimationCallback(mTutorialHandler).addOneHandedAnimationCallback(mBackgroundPanelOrganizer).setDuration(durationMs).start();}}

OneHandedAnimationController处理过程中会有动画处理,而主要针对SurfaceControl做处理：

                @Overridevoid applySurfaceControlTransaction(SurfaceControl leash,SurfaceControl.Transaction tx, float fraction) {final float start = getStartValue();final float end = getEndValue();final float currentValue = getCastedFractionValue(start, end, fraction);mTmpRect.set(mTmpRect.left,mTmpRect.top + Math.round(currentValue),mTmpRect.right,mTmpRect.bottom + Math.round(currentValue));setCurrentValue(currentValue);getSurfaceTransactionHelper().crop(tx, leash, mTmpRect).round(tx, leash).translate(tx, leash, currentValue);tx.apply();}

getSurfaceTransactionHelper返回的是OneHandedSurfaceTransactionHelper，其整合了一些对SurfaceControl的方法：

    /*** Operates the translation (setPosition) on a given transaction and leash** @return same {@link OneHandedSurfaceTransactionHelper} instance for method chaining*/OneHandedSurfaceTransactionHelper translate(SurfaceControl.Transaction tx, SurfaceControl leash,float offset) {tx.setPosition(leash, 0, offset);return this;}/*** Operates the crop (setMatrix) on a given transaction and leash** @return same {@link OneHandedSurfaceTransactionHelper} instance for method chaining*/OneHandedSurfaceTransactionHelper crop(SurfaceControl.Transaction tx, SurfaceControl leash,Rect destinationBounds) {tx.setWindowCrop(leash, destinationBounds.width(), destinationBounds.height());return this;}/*** Operates the round corner radius on a given transaction and leash** @return same {@link OneHandedSurfaceTransactionHelper} instance for method chaining*/OneHandedSurfaceTransactionHelper round(SurfaceControl.Transaction tx, SurfaceControl leash) {if (mEnableCornerRadius) {tx.setCornerRadius(leash, mCornerRadius);}return this;}

setWindowCrop设置裁切大小，setCornerRadius设置圆角，setPosition设置位置。

(2)单手模式触摸事件管理

com.android.wm.shell.onehanded.OneHandedTouchHandler

当触摸非应用界面的位置时，回调OneHandedController.stopOneHanded,推出单手模式:

    private boolean onMotionEvent(MotionEvent ev) {mIsInOutsideRegion = isWithinTouchOutsideRegion(ev.getX(), ev.getY());switch (ev.getAction()) {case MotionEvent.ACTION_DOWN:case MotionEvent.ACTION_MOVE: {if (!mIsInOutsideRegion) {mTimeoutHandler.resetTimer();}break;}case MotionEvent.ACTION_UP:case MotionEvent.ACTION_CANCEL: {mTimeoutHandler.resetTimer();if (mIsInOutsideRegion && !mIsOnStopTransitioning)  {mTouchEventCallback.onStop();mIsOnStopTransitioning = true;}// Reset flag for next operationmIsInOutsideRegion = false;break;}}return true;}