andorid中dispatchkeyevent事件传递及焦点获取

DalvikVM[localhost:8601]
Thread [<1> main] (Suspended (breakpoint at line 740 in Workspace))
<VM does not provide monitor information>
Workspace.dispatchKeyEvent(KeyEvent) line: 740
FrameLayout(ViewGroup).dispatchKeyEvent(KeyEvent) line: 1246
FrameLayout(ViewGroup).dispatchKeyEvent(KeyEvent) line: 1246
FrameLayout(ViewGroup).dispatchKeyEvent(KeyEvent) line: 1246
LinearLayout(ViewGroup).dispatchKeyEvent(KeyEvent) line: 1246
PhoneWindow$DecorView(ViewGroup).dispatchKeyEvent(KeyEvent) line: 1246
PhoneWindow$DecorView.superDispatchKeyEvent(KeyEvent) line: 1879
PhoneWindow.superDispatchKeyEvent(KeyEvent) line: 1361
Launcher(Activity).dispatchKeyEvent(KeyEvent) line: 2324
Launcher.dispatchKeyEvent(KeyEvent) line: 6542
PhoneWindow$DecorView.dispatchKeyEvent(KeyEvent) line: 1806
ViewRootImpl.deliverKeyEventPostIme(KeyEvent, boolean) line: 3327
ViewRootImpl.handleFinishedEvent(int, boolean) line: 3300
ViewRootImpl.handleMessage(Message) line: 2460
ViewRootImpl(Handler).dispatchMessage(Message) line: 99
Looper.loop() line: 137
ActivityThread.main(String[]) line: 4429
Method.invokeNative(Object, Object[], Class, Class[], Class, int, boolean) line: not available [native method]
Method.invoke(Object, Object...) line: 511
ZygoteInit$MethodAndArgsCaller.run() line: 795
ZygoteInit.main(String[]) line: 562
NativeStart.main(String[]) line: not available [native method]
Thread [<10> Binder Thread #2] (Running)
Thread [<9> Binder Thread #1] (Running)
Daemon Thread [<8> FinalizerWatchdogDaemon] (Running)
Daemon Thread [<7> FinalizerDaemon] (Running)
Daemon Thread [<6> ReferenceQueueDaemon] (Running)
Daemon Thread [<11> java.lang.ProcessManager] (Running)
Thread [<12> launcher-loader] (Running)
Thread [<13> launcher-loader] (Running)
Thread [<15> Timer-1] (Running)
Thread [<14> Timer-0] (Running)
Thread [<18> SoundPool] (Running)
Thread [<19> SoundPoolThread] (Running)
Thread [<20> Thread-96] (Running)
Thread [<21> DaemonThread] (Running)
Thread [<17> SerialHandler] (Running)
Daemon Thread [<22> RefQueueWorker@org.apache.http.impl.conn.tsccm.ConnPoolByRoute@4202f9a8] (Running)
Thread [<25> Thread-104] (Running)
Thread [<26> pool-2-thread-1] (Running)
Thread [<28> pool-2-thread-2] (Running)
Thread [<29> pool-2-thread-3] (Running)
Thread [<30> pool-2-thread-4] (Running)
Thread [<31> pool-2-thread-5] (Running)
Thread [<32> pool-2-thread-6] (Running)
Thread [<33> pool-2-thread-7] (Running)
Thread [<34> pool-2-thread-8] (Running)
Thread [<35> pool-2-thread-9] (Running)
Thread [<36> pool-2-thread-10] (Running)
Thread [<16> Binder Thread #3] (Running)
Thread [<39> AsyncTask #5] (Running)
Thread [<40> AsyncTask #6] (Running)
Thread [<42> AsyncTask #8] (Running)
Thread [<44> AsyncTask #10] (Running)
Thread [<49> AsyncTask #15] (Running)
Thread [<27> Thread-149] (Running)

从以上我们可以看到事件是通过顶层view往下传递的

再查看viewgroup源码

public boolean dispatchKeyEvent(KeyEvent event) {
if (mInputEventConsistencyVerifier != null) {
mInputEventConsistencyVerifier.onKeyEvent(event, 1);
}

if ((mPrivateFlags & (FOCUSED | HAS_BOUNDS)) == (FOCUSED | HAS_BOUNDS)) {
if (super.dispatchKeyEvent(event)) {
return true;
}
} else if (mFocused != null && (mFocused.mPrivateFlags & HAS_BOUNDS) == HAS_BOUNDS) {
if (mFocused.dispatchKeyEvent(event)) {
return true;
}
}

if (mInputEventConsistencyVerifier != null) {
mInputEventConsistencyVerifier.onUnhandledEvent(event, 1);
}
return false;
}

是从focused view往下传递事件

可以参考：

Android 中keyEvent的消息处理

再来按home键，从新获取焦点的处理：

Home键
2.6_BesTVLauncherInside [Android Application]
DalvikVM[localhost:8601]
Thread [<1> main] (Suspended (breakpoint at line 50 in TintView$1))
<VM does not provide monitor information>
TintView$1.onFocusChange(View, boolean) line: 50
FocusView(View).onFocusChanged(boolean, int, Rect) line: 3863
FocusView(CusFocusView).onFocusChanged(boolean, int, Rect) line: 205
FocusView(View).handleFocusGainInternal(int, Rect) line: 3685
FocusView(View).requestFocus(int, Rect) line: 5378
TintView(ViewGroup).onRequestFocusInDescendants(int, Rect) line: 2154
TintView(ViewGroup).requestFocus(int, Rect) line: 2110
LinearLayout(ViewGroup).onRequestFocusInDescendants(int, Rect) line: 2154
LinearLayout(ViewGroup).requestFocus(int, Rect) line: 2110
FrameLayout(ViewGroup).onRequestFocusInDescendants(int, Rect) line: 2154
FrameLayout(ViewGroup).requestFocus(int, Rect) line: 2110
FrameLayout(ViewGroup).onRequestFocusInDescendants(int, Rect) line: 2154
FrameLayout(ViewGroup).requestFocus(int, Rect) line: 2110
FrameLayout(ViewGroup).onRequestFocusInDescendants(int, Rect) line: 2154
FrameLayout(ViewGroup).requestFocus(int, Rect) line: 2110
LinearLayout(ViewGroup).onRequestFocusInDescendants(int, Rect) line: 2154
LinearLayout(ViewGroup).requestFocus(int, Rect) line: 2110
PhoneWindow$DecorView(ViewGroup).onRequestFocusInDescendants(int, Rect) line: 2154
PhoneWindow$DecorView(ViewGroup).requestFocus(int, Rect) line: 2113
PhoneWindow$DecorView(View).requestFocus(int) line: 5328
ViewRootImpl.clearChildFocus(View) line: 2200
PhoneWindow$DecorView(ViewGroup).clearChildFocus(View) line: 669
LinearLayout(ViewGroup).clearChildFocus(View) line: 669
FrameLayout(ViewGroup).clearChildFocus(View) line: 669
FrameLayout(ViewGroup).clearChildFocus(View) line: 669
FrameLayout(ViewGroup).clearChildFocus(View) line: 669
Workspace(ViewGroup).clearChildFocus(View) line: 669
ChildLayout(ViewGroup).clearChildFocus(View) line: 669
CellLayout(ViewGroup).clearChildFocus(View) line: 669
FrameView(ViewGroup).clearChildFocus(View) line: 669
FrameLayout(ViewGroup).clearChildFocus(View) line: 669
FocusView(View).clearFocus() line: 3756
FrameLayout(ViewGroup).clearFocus() line: 682
FrameView(ViewGroup).clearFocus() line: 682
CellLayout(ViewGroup).clearFocus() line: 682
ChildLayout(ViewGroup).clearFocus() line: 682
Workspace.snapToScreen(int, int, boolean) line: 1448
Workspace.snapToScreen(int) line: 1422
Workspace.scrollFirst() line: 1562
Launcher.onNewIntent(Intent) line: 1658
Instrumentation.callActivityOnNewIntent(Activity, Intent) line: 1123
ActivityThread.deliverNewIntents(ActivityThread$ActivityClientRecord, List) line: 2042
ActivityThread.performNewIntents(IBinder, List) line: 2055
ActivityThread.handleNewIntent(ActivityThread$NewIntentData) line: 2064
ActivityThread.access$1400(ActivityThread, ActivityThread$NewIntentData) line: 123
ActivityThread$H.handleMessage(Message) line: 1194
ActivityThread$H(Handler).dispatchMessage(Message) line: 99
Looper.loop() line: 137
ActivityThread.main(String[]) line: 4429
Method.invokeNative(Object, Object[], Class, Class[], Class, int, boolean) line: not available [native method]
Method.invoke(Object, Object...) line: 511
ZygoteInit$MethodAndArgsCaller.run() line: 795
ZygoteInit.main(String[]) line: 562
NativeStart.main(String[]) line: not available [native method]
Thread [<10> Binder Thread #2] (Running)
Thread [<9> Binder Thread #1] (Running)
Daemon Thread [<8> FinalizerWatchdogDaemon] (Running)
Daemon Thread [<7> FinalizerDaemon] (Running)
Daemon Thread [<6> ReferenceQueueDaemon] (Running)
Daemon Thread [<11> java.lang.ProcessManager] (Running)
Thread [<12> launcher-loader] (Running)
Thread [<13> launcher-loader] (Running)
Thread [<15> Timer-1] (Running)
Thread [<14> Timer-0] (Running)
Thread [<18> SoundPool] (Running)
Thread [<19> SoundPoolThread] (Running)
Thread [<20> Thread-96] (Running)
Thread [<21> DaemonThread] (Running)
Thread [<17> SerialHandler] (Running)
Daemon Thread [<22> RefQueueWorker@org.apache.http.impl.conn.tsccm.ConnPoolByRoute@4202f9a8] (Running)
Thread [<25> Thread-104] (Running)
Thread [<26> pool-2-thread-1] (Running)
Thread [<28> pool-2-thread-2] (Running)
Thread [<29> pool-2-thread-3] (Running)
Thread [<30> pool-2-thread-4] (Running)
Thread [<31> pool-2-thread-5] (Running)
Thread [<32> pool-2-thread-6] (Running)
Thread [<33> pool-2-thread-7] (Running)
Thread [<34> pool-2-thread-8] (Running)
Thread [<35> pool-2-thread-9] (Running)
Thread [<36> pool-2-thread-10] (Running)
Thread [<16> Binder Thread #3] (Running)
Thread [<39> AsyncTask #5] (Running)
Thread [<40> AsyncTask #6] (Running)
Thread [<42> AsyncTask #8] (Running)
Thread [<44> AsyncTask #10] (Running)
Thread [<49> AsyncTask #15] (Running)

ChildLayout(ViewGroup).clearFocus() line: 682

Workspace.snapToScreen(int, int, boolean) line: 1448
调用了clearfocus

viewgroup中：

/**
* {@inheritDoc}
*/
@Override
public void clearFocus() {
super.clearFocus();

// clear any child focus if it exists
if (mFocused != null) {
mFocused.clearFocus();
}
}

view中：

public void clearFocus() {
if (DBG) {
System.out.println(this + " clearFocus()");
}

if ((mPrivateFlags & FOCUSED) != 0) {
mPrivateFlags &= ~FOCUSED;

if (mParent != null) {
mParent.clearChildFocus(this);
}

onFocusChanged(false, 0, null);
refreshDrawableState();
}
}

</pre><pre code_snippet_id="626730" snippet_file_name="blog_20150324_7_4283735" name="code" class="java"><span style="white-space:pre">		</span>

ViewRootImpl.clearChildFocus(View) line: 2200<span style="white-space:pre">	</span>

</pre>viewrootimpl中：<p></p><p></p><pre code_snippet_id="626730" snippet_file_name="blog_20150324_10_4665189" name="code" class="java">    public void clearChildFocus(View child) {
checkThread();

View oldFocus = mFocusedView;

if (DEBUG_INPUT_RESIZE) Log.v(TAG, "Clearing child focus");
mFocusedView = mRealFocusedView = null;
if (mView != null && !mView.hasFocus()) {
// If a view gets the focus, the listener will be invoked from requestChildFocus()
if (!mView.requestFocus(View.FOCUS_FORWARD)) {
mAttachInfo.mTreeObserver.dispatchOnGlobalFocusChange(oldFocus, null);
}
} else if (oldFocus != null) {
mAttachInfo.mTreeObserver.dispatchOnGlobalFocusChange(oldFocus, null);
}
}

viewgroup中：

<pre name="code" class="java">    protected boolean onRequestFocusInDescendants(int direction,
Rect previouslyFocusedRect) {
int index;
int increment;
int end;
int count = mChildrenCount;
if ((direction & FOCUS_FORWARD) != 0) {
index = 0;
increment = 1;
end = count;
} else {
index = count - 1;
increment = -1;
end = -1;
}
final View[] children = mChildren;
for (int i = index; i != end; i += increment) {
View child = children[i];
if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE) {
if (child.requestFocus(direction, previouslyFocusedRect)) {
return true;
}
}
}
return false;
}

children[i]中的第一个节点最先获取焦点