Android 7.0 锁屏解锁之向上滑动显示解锁界面分析

by jing.chen

锁屏的解锁操作是在锁屏界面向上滑动实现的，通过向上滑动调出解锁界面(如图案、PIN、密码解锁界面)，在解锁界面输入正确的密码之后解锁显示launcher。向上滑动如何调出解锁界面，需要分析PanelView的onTouchEvent事件，用户向上滑动的整个touch事件分析如下：

1、用户手指touch屏幕，产生touch down事件，最底层view StatusBarWindowView会执行onInterceptTouchEvent，看是否需要拦截touch事件，touch down事件在此没有被拦截，再一级级往子View传递，都没有被拦截，之后执行OnTouchEvent，从子View开始往父View传递，一级级往父View传递，也都没有消耗touch down事件；

2、用户移动手指，产生touch move事件，最底层view StatusBarWindowView会执行onInterceptTouchEvent，看是否需要拦截touch事件，touch move事件在此也没有被拦截，再一级级往子View传递，都没有被拦截，之后执行OnTouchEvent，从子View开始往父View传递，一级级往父View传递，到PanelView这里当手指移动的距离达到一定的阈值会调用onTrackingStarted从而设置mTracking的值为true，接收此touch move事件，之后的touch事件直接传到此View。在用户滑动过程会调用setExpandedHeightInternal,进而调用NotificationPanelView的onHeightUpdated进行锁屏上的时间和通知View根据手指的移动距离进行缩小、变透明处理；

3、用户抬起手指，产生touch up事件，PanelView接收到这个事件后会调用endMotionEvent，如果手指从down到up之间移动的距离达到一定阈值会调用onTrackingStopped，从而调出解锁界面；

代码分析如下：

PanelView.java

@Override

public boolean onTouchEvent(MotionEvent event) {

...

final float x = event.getX(pointerIndex);

final float y = event.getY(pointerIndex);

if (event.getActionMasked() == MotionEvent.ACTION_DOWN) {

mGestureWaitForTouchSlop = isFullyCollapsed() || hasConflictingGestures();

mIgnoreXTouchSlop = isFullyCollapsed() || shouldGestureIgnoreXTouchSlop(x, y);

}

switch (event.getActionMasked()) {

...

case MotionEvent.ACTION_MOVE:

float h = y - mInitialTouchY;

// If the panel was collapsed when touching, we only need to check for the

// y-component of the gesture, as we have no conflicting horizontal gesture.

if (Math.abs(h) > mTouchSlop

&& (Math.abs(h) > Math.abs(x - mInitialTouchX)

|| mIgnoreXTouchSlop)) {

mTouchSlopExceeded = true;

if (mGestureWaitForTouchSlop && !mTracking && !mCollapsedAndHeadsUpOnDown) {

if (!mJustPeeked && mInitialOffsetOnTouch != 0f) {

startExpandMotion(x, y, false /* startTracking */, mExpandedHeight);

h = 0;

}

cancelHeightAnimator();

removeCallbacks(mPeekRunnable);

mPeekPending = false;

onTrackingStarted();//向上滑动时，手指移动的距离达到一定的阈值会调用onTrackingStarted，设置mTracking值为true，从而接收touch事件

}

}

final float newHeight = Math.max(0, h + mInitialOffsetOnTouch);

if (newHeight > mPeekHeight) {

if (mPeekAnimator != null) {

mPeekAnimator.cancel();

}

mJustPeeked = false;

}

if (-h >= getFalsingThreshold()) {

mTouchAboveFalsingThreshold = true;

mUpwardsWhenTresholdReached = isDirectionUpwards(x, y);

}

if (!mJustPeeked && (!mGestureWaitForTouchSlop || mTracking) && !isTrackingBlocked()) {

setExpandedHeightInternal(newHeight);//用户滑动过程会调用setExpandedHeightInternal,进而调用NotificationPanelView的onHeightUpdated进行锁屏上的时间和通知View根据手指的移动距离进行缩小、变透明处理

}

trackMovement(event);

break;

case MotionEvent.ACTION_UP:

case MotionEvent.ACTION_CANCEL:

trackMovement(event);

endMotionEvent(event, x, y, false /* forceCancel */);

break;

}

return !mGestureWaitForTouchSlop || mTracking;

}

protected void onTrackingStarted() {

endClosing();

mTracking = true;

mCollapseAfterPeek = false;

mBar.onTrackingStarted();

notifyExpandingStarted();

notifyBarPanelExpansionChanged();

}

NotificationPanelView.java

@Override

protected void onHeightUpdated(float expandedHeight, boolean isMovingInKeyguard) {

mExpandedHeightTpv = expandedHeight;

LogUtils.d(TAG,"--------onHeightUpdated");

if (!mQsExpanded || mQsExpandImmediate || mIsExpanding && mQsExpandedWhenExpandingStarted) {

positionClockAndNotifications(isMovingInKeyguard);//锁屏上的时间和通知View根据手指的移动距离进行缩小、变透明处理

}

...

}

endMotionEvent调出解锁界面流程如下：

->PanelView.endMotionEvent(MotionEvent event, float x, float y, boolean forceCancel)

->NotificationPanelView.onTrackingStopped(boolean expand)

->PhoneStatusBar.onTrackingStopped(boolean expand)

->PhoneStatusBar.showBouncer()

->StatusBarKeyguardViewManager.dismiss()

->StatusBarKeyguardViewManager.dismiss(boolean authenticated)

->StatusBarKeyguardViewManager.showBouncer(boolean authenticated)

->KeyguardBouncer.show(boolean resetSecuritySelection, boolean authenticated)

->KeyguardBouncer.mShowRunnable

调用KeyguardBouncer.show(boolean resetSecuritySelection, boolean authenticated)方法并没有重新加载解锁界面，解锁界面是在灭屏时调用StatusBarKeyguardViewManager.reset后重新inflate进来的，在此处只是通过KeyguardBouncer.mShowRunnable将这个解锁界面显示出来，灭屏时解锁界面的调用栈如下：

“main@52911” prio=5 tid=0x1 nid=NA runnable

java.lang.Thread.State: RUNNABLE

at com.android.keyguard.KeyguardSecurityContainer.showSecurityScreen(KeyguardSecurityContainer.java:584)

at com.android.keyguard.KeyguardSecurityContainer.showPrimarySecurityScreen(KeyguardSecurityContainer.java:416)

at com.android.keyguard.KeyguardHostView.onFinishInflate(KeyguardHostView.java:168)

at android.view.LayoutInflater.rInflate(LayoutInflater.java:867)

at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:821)

at android.view.LayoutInflater.parseInclude(LayoutInflater.java:994)

at android.view.LayoutInflater.rInflate(LayoutInflater.java:854)

at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:821)

at android.view.LayoutInflater.inflate(LayoutInflater.java:518)

- locked <0xd005> (a java.lang.Object[])

at android.view.LayoutInflater.inflate(LayoutInflater.java:426)

at android.view.LayoutInflater.inflate(LayoutInflater.java:377)

at com.android.systemui.statusbar.phone.KeyguardBouncer.inflateView(KeyguardBouncer.java:317)

at com.android.systemui.statusbar.phone.KeyguardBouncer.ensureView(KeyguardBouncer.java:307)

at com.android.systemui.statusbar.phone.KeyguardBouncer.needsFullscreenBouncer(KeyguardBouncer.java:347)

at com.android.systemui.statusbar.phone.StatusBarKeyguardViewManager.showBouncerOrKeyguard(StatusBarKeyguardViewManager.java:130)

at com.android.systemui.statusbar.phone.StatusBarKeyguardViewManager.reset(StatusBarKeyguardViewManager.java:192)

至此把用户设定的解锁界面(图案、密码、PIN码)显示出来