background
We often encounter an Application does not hava focused windowexception ANR. This exception is usually caused by the FocusedWindow not having the focus window, and this type of exception will only occur when the key event is dispatched , because the key event needs to find a focused window and then dispatch it, while the touch event Just find the currently displayed window
Focus window settings
WMS only manages windows, and cannot determine whether there is a window covering the current screen.
SurfaceFlinger manages the display, which is closest to the screen seen by the user. It can know whether there is a window covering the current screen, and sets the corresponding window information based on the real display window. InputDispatcher
Key log
window
View mCurrentFocus and mFocusedApp in dumpsys window
mCurrentFocus=Window{
f96644 u0 NotificationShade}
mFocusedApp=ActivityRecord{
e9566ee u0 com.android.launcher3/.uioverrides.QuickstepLauncher} t12}
mCurrentFocusRefers to the current focus window
mFocusedApprefers to the current focus Activity
Check if there is LAST ANR
WINDOW MANAGER LAST ANR (dumpsys window lastanr)
<no ANR has occurred since boot>
There is no LAST ANR here, if there is, mCurrentFocus will show null
SurfaceFlinger
View HWC layers in dumpsys SurfaceFlinger
Display 4619827259835644672 (active) HWC layers:
---------------------------------------------------------------------------------------------------------------------------------------------------------------
Layer name
Z | Window Type | Comp Type | Transform | Disp Frame (LTRB) | Source Crop (LTRB) | Frame Rate (Explicit) (Seamlessness) [Focused]
---------------------------------------------------------------------------------------------------------------------------------------------------------------
com.example.mysystemdialog/com.example.mysystemdialog.MainActivity#118
rel 0 | 1 | CLIENT | 0 | 0 0 1440 2960 | 0.0 0.0 1440.0 2960.0 | [*]
---------------------------------------------------------------------------------------------------------------------------------------------------------------
StatusBar#75
rel 0 | 2000 | CLIENT | 0 | 0 0 1440 84 | 0.0 0.0 1440.0 84.0 | [ ]
---------------------------------------------------------------------------------------------------------------------------------------------------------------
NavigationBar0#74
rel 0 | 2019 | CLIENT | 0 | 0 2792 1440 2960 | 0.0 0.0 1440.0 168.0 | [ ]
---------------------------------------------------------------------------------------------------------------------------------------------------------------
[Focused]If this column is marked with [*], it means it is the focus window.
input
View FocusedApplications and FocusedWindows in dumpsys input
FocusedApplications:
displayId=0, name='ActivityRecord{e9566ee u0 com.android.launcher3/.uioverrides.QuickstepLauncher} t12}', dispatchingTimeout=5000ms
FocusedWindows:
displayId=0, name='f96644 NotificationShade'
If ANR occurs, the focus window will be dumpsys input.
Input Dispatcher State at time of last ANR:
ANR:
Time:......
Reason:......
Window:......
FocusedApplications:......
FocusedWindows: <none>
event log
05-18 19:22:55.806 580 607 I input_focus: [Focus request f96644 NotificationShade,reason=UpdateInputWindows]
05-18 19:22:55.837 580 675 I input_focus: [Focus leaving e225d94 com.android.launcher3/com.android.launcher3.uioverrides.QuickstepLauncher (server),reason=Waiting for window because NO_WINDOW]
05-18 19:22:55.855 580 675 I input_focus: [Focus entering f96644 NotificationShade (server),reason=Window became focusable. Previous reason: NOT_VISIBLE]
requestThere is a one-to-one correspondence with enteringthe normal situation. If it is printed, enteringit means that the real focus has entered the corresponding window. When this
occurs Application does not hava focused window, there is usually requestprinting. We can analyze it by whether enteringthere is printing.
1. enteringIf there is some printing, it means that the focus is already in the input. , but there is still ANR, you need to analyze it from the input and other aspects .
2. enteringPart of it is not printed, which means that the input is not triggered and the focus window is set to the input. You need to check SurfaceFlinger or WMS.