日期：
来源：郭霖收集编辑：a5right
https://lyldalek.top/
/**
* Extended implementation of activity launch. Used when server requests a launch or relaunch.
*/
@Override
public Activity handleLaunchActivity(ActivityClientRecord r,
PendingTransactionActions pendingActions, Intent customIntent) {
...
// ① 这里是启动了渲染线程
HardwareRenderer.preload();
...
// ② 获取 WMS 对象
WindowManagerGlobal.initialize();
// ③ 继续启动 activity
final Activity a = performLaunchActivity(r, customIntent);
return a;
}
/** Core implementation of activity launch. */
private Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {
...
try {
// ① 创建出来了 activity 对象
java.lang.ClassLoader cl = appContext.getClassLoader();
activity = mInstrumentation.newActivity(
cl, component.getClassName(), r.intent);
...
} catch (Exception e) {
...
}
try {
if (activity != null) {
...
// ② 执行 activity 的 attach 方法
activity.attach(appContext, this, getInstrumentation(), r.token,
r.ident, app, r.intent, r.activityInfo, title, r.parent,
r.embeddedID, r.lastNonConfigurationInstances, config,
r.referrer, r.voiceInteractor, window, r.activityConfigCallback,
r.assistToken, r.shareableActivityToken);
...
// ③ 执行 activity 的 onCreate 方法
if (r.isPersistable()) {
mInstrumentation.callActivityOnCreate(activity, r.state, r.persistentState);
} else {
mInstrumentation.callActivityOnCreate(activity, r.state);
}
...
}
...
} catch (SuperNotCalledException e) {
...
}
return activity;
}
class H extends Handler {
...
public void handleMessage(Message msg) {
...
switch (msg.what) {
...
case EXECUTE_TRANSACTION:
final ClientTransaction transaction = (ClientTransaction) msg.obj;
mTransactionExecutor.execute(transaction);
...
break;
...
}
}
}
public class LaunchActivityItem extends ClientTransactionItem {
...
@Override
public void execute(ClientTransactionHandler client, IBinder token,
PendingTransactionActions pendingActions) {
Trace.traceBegin(TRACE_TAG_ACTIVITY_MANAGER, "activityStart");
ActivityClientRecord r = new ActivityClientRecord(token, mIntent, mIdent, mInfo,
mOverrideConfig, mCompatInfo, mReferrer, mVoiceInteractor, mState, mPersistentState,
mPendingResults, mPendingNewIntents, mActivityOptions, mIsForward, mProfilerInfo,
client, mAssistToken, mShareableActivityToken, mLaunchedFromBubble,
mTaskFragmentToken);
client.handleLaunchActivity(r, pendingActions, null /* customIntent */);
Trace.traceEnd(TRACE_TAG_ACTIVITY_MANAGER);
}
...
}
class MainActivity : AppCompatActivity() {
private lateinit var binding: ActivityMainBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
// 使用了 ViewBinding
binding = ActivityMainBinding.inflate(layoutInflater)
// ① 加载 activity 的布局
setContentView(binding.root)
}
}
@Override
public void setContentView(View view) {
initViewTreeOwners();
getDelegate().setContentView(view);
}
@Override
public void setContentView(View v) {
ensureSubDecor();
ViewGroup contentParent = mSubDecor.findViewById(android.R.id.content);
contentParent.removeAllViews();
contentParent.addView(v);
...
}
private ViewGroup createSubDecor() {
...
mWindow.setContentView(subDecor);
...
}
@Override
public void setContentView(View view, ViewGroup.LayoutParams params) {
...
if (hasFeature(FEATURE_CONTENT_TRANSITIONS)) {
view.setLayoutParams(params);
final Scene newScene = new Scene(mContentParent, view);
transitionTo(newScene);
} else {
mContentParent.addView(view, params);
}
mContentParent.requestApplyInsets();
final Callback cb = getCallback();
if (cb != null && !isDestroyed()) {
cb.onContentChanged();
}
mContentParentExplicitlySet = true;
}
@Override
public void handleResumeActivity(ActivityClientRecord r, boolean finalStateRequest,
boolean isForward, String reason) {
...
// ① 这里调用了 activity 的 onResume 方法
if (!performResumeActivity(r, finalStateRequest, reason)) {
return;
}
...
if (r.window == null && !a.mFinished && willBeVisible) {
r.window = r.activity.getWindow();
View decor = r.window.getDecorView();
decor.setVisibility(View.INVISIBLE);
ViewManager wm = a.getWindowManager();
WindowManager.LayoutParams l = r.window.getAttributes();
...
if (a.mVisibleFromClient) {
if (!a.mWindowAdded) {
a.mWindowAdded = true;
// ② 这里将 decorView 添加到了 windowManager 上
wm.addView(decor, l);
} else {
..
}
}
...
} else if (!willBeVisible) {
...
}
...
}
public void addView(View view, ViewGroup.LayoutParams params,
Display display, Window parentWindow, int userId) {
...
ViewRootImpl root;
View panelParentView = null;
synchronized (mLock) {
...
// ① 创建了一个 ViewRootImpl 对象。
if (windowlessSession == null) {
root = new ViewRootImpl(view.getContext(), display);
} else {
root = new ViewRootImpl(view.getContext(), display,
windowlessSession);
}
view.setLayoutParams(wparams);
// ② 添加 View 到集合
mViews.add(view);
mRoots.add(root);
mParams.add(wparams);
// do this last because it fires off messages to start doing things
try {
// ③ 将 DecorView 与 ViewRootImpl 关联起来
root.setView(view, wparams, panelParentView, userId);
} catch (RuntimeException e) {
...
}
}
}
public void setView(View view, WindowManager.LayoutParams attrs, View panelParentView,
int userId) {
...
mView = view;
...
requestLayout();
...
}
@Override
public void requestLayout() {
if (!mHandlingLayoutInLayoutRequest) {
// ① 这里检查的线程
checkThread();
mLayoutRequested = true;
// ② 准备开始遍历 View 树
scheduleTraversals();
}
}
void scheduleTraversals() {
// 过滤
if (!mTraversalScheduled) {
mTraversalScheduled = true;
// ① 往消息队列里面发送一个同步屏障
mTraversalBarrier = mHandler.getLooper().getQueue().postSyncBarrier();
// ② 向 CALLBACK_TRAVERSAL 队列里面添加一个 runnable
mChoreographer.postCallback(
Choreographer.CALLBACK_TRAVERSAL, mTraversalRunnable, null);
...
}
}
private Choreographer(Looper looper, int vsyncSource) {
mLooper = looper;
// handler
mHandler = new FrameHandler(looper);
// 初始化 FrameDisplayEventReceiver ，与 SurfaceFlinger 建立通信用于接收和请求 Vsync
mDisplayEventReceiver = USE_VSYNC
? new FrameDisplayEventReceiver(looper, vsyncSource)
: null;
...
// 创建了5个队列
// CALLBACK_ANIMATION - CALLBACK_INSETS_ANIMATION - CALLBACK_TRAVERSAL - CALLBACK_COMMIT - unknown
mCallbackQueues = new CallbackQueue[CALLBACK_LAST + 1];
for (int i = 0; i <= CALLBACK_LAST; i++) {
mCallbackQueues[i] = new CallbackQueue();
}
...
}
private final class FrameDisplayEventReceiver extends DisplayEventReceiver
implements Runnable {
...
@Override
public void onVsync(long timestampNanos, long physicalDisplayId, int frame,
VsyncEventData vsyncEventData) {
try {
...
// ① 发送了一个异步消息，将 this 传进去
Message msg = Message.obtain(mHandler, this);
msg.setAsynchronous(true);
mHandler.sendMessageAtTime(msg, timestampNanos / TimeUtils.NANOS_PER_MS);
} finally {
...
}
}
@Override
public void run() {
...
// 调用 doFrame 方法
doFrame(mTimestampNanos, mFrame, mLastVsyncEventData);
}
}
private void postCallbackDelayedInternal(int callbackType,
Object action, Object token, long delayMillis) {
...
synchronized (mLock) {
...
if (dueTime <= now) {
// 超时了，直接调用 doFrame
scheduleFrameLocked(now);
} else {
// 发送一个异步消息
Message msg = mHandler.obtainMessage(MSG_DO_SCHEDULE_CALLBACK, action);
msg.arg1 = callbackType;
msg.setAsynchronous(true);
mHandler.sendMessageAtTime(msg, dueTime);
}
}
}
private void scheduleFrameLocked(long now) {
if (!mFrameScheduled) {
mFrameScheduled = true;
if (USE_VSYNC) {
...
if (isRunningOnLooperThreadLocked()) {
...
} else {
Message msg = mHandler.obtainMessage(MSG_DO_SCHEDULE_VSYNC);
msg.setAsynchronous(true);
mHandler.sendMessageAtFrontOfQueue(msg);
}
} else {
...
}
}
}
private final class FrameHandler extends Handler {
...
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_DO_FRAME:
doFrame(System.nanoTime(), 0, new DisplayEventReceiver.VsyncEventData());
break;
case MSG_DO_SCHEDULE_VSYNC:
doScheduleVsync();
break;
case MSG_DO_SCHEDULE_CALLBACK:
doScheduleCallback(msg.arg1);
break;
}
}
}
void doScheduleCallback(int callbackType) {
synchronized (mLock) {
if (!mFrameScheduled) {
final long now = SystemClock.uptimeMillis();
if (mCallbackQueues[callbackType].hasDueCallbacksLocked(now)) {
scheduleFrameLocked(now);
}
}
}
}
void doFrame(long frameTimeNanos, int frame,
DisplayEventReceiver.VsyncEventData vsyncEventData) {
...
try {
...
doCallbacks(Choreographer.CALLBACK_INPUT, frameData, frameIntervalNanos);
mFrameInfo.markAnimationsStart();
doCallbacks(Choreographer.CALLBACK_ANIMATION, frameData, frameIntervalNanos);
doCallbacks(Choreographer.CALLBACK_INSETS_ANIMATION, frameData,
frameIntervalNanos);
mFrameInfo.markPerformTraversalsStart();
doCallbacks(Choreographer.CALLBACK_TRAVERSAL, frameData, frameIntervalNanos);
doCallbacks(Choreographer.CALLBACK_COMMIT, frameData, frameIntervalNanos);
} finally {
...
}
...
}
Choreographer.CALLBACK_INPUT 就是事件队列，事件的处理就在这个里面执行。 Choreographer.CALLBACK_ANIMATION 就是动画队列，比如 fling 等动画就在里面执行。 Choreographer.CALLBACK_TRAVERSAL 就是执行 View 树的构建与限制。ViewRootImpl 在 scheduleTraversals 的时候 post 的 runnable 就储存在了这里，在这里被执行。
private void performTraversals() {
...
if (mFirst) {
...
// ① 这里调用了 View 和 listener 的 onWindowAttached 方法
host.dispatchAttachedToWindow(mAttachInfo, 0);
mAttachInfo.mTreeObserver.dispatchOnWindowAttachedChange(true);
...
}
...
// ②
getRunQueue().executeActions(mAttachInfo.mHandler);
...
}
override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec)
val w = calW()
val h = calH()
val fixW = resolveSize(w, widthMeasureSpec)
val fixH = resolveSize(h, heightMeasureSpec)
setMeasuredDimension(fixW, fixH)
}
class TestView @JvmOverloads constructor(
context: Context,
attrs: AttributeSet? = null,
defStyleAttr: Int = 0
) : View(context, attrs, defStyleAttr) {
override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec)
setMeasuredDimension(100, 100)
}
}
https://blog.csdn.net/aigestudio/category_9263410.html
/**
* Don't call or override this method. It is used for the implementation of
* the view hierarchy.
*
* @deprecated Use {@link #onDescendantInvalidated(View, View)} instead to observe updates to
* draw state in descendants.
*/
@Deprecated
@Override
public final void invalidateChild(View child, final Rect dirty) {
final AttachInfo attachInfo = mAttachInfo;
if (attachInfo != null && attachInfo.mHardwareAccelerated) {
// HW accelerated fast path
// ① 硬件加速走这个分支
onDescendantInvalidated(child, child);
return;
}
ViewParent parent = this;
if (attachInfo != null) {
...
do {
...
// ② 非硬件加速走这个分支
parent = parent.invalidateChildInParent(location, dirty);
if (view != null) {
...
}
} while (parent != null);
}
}
@Override
public void onDescendantInvalidated(@NonNull View child, @NonNull View descendant) {
// TODO: Re-enable after camera is fixed or consider targetSdk checking this
// checkThread();
if ((descendant.mPrivateFlags & PFLAG_DRAW_ANIMATION) != 0) {
mIsAnimating = true;
}
invalidate();
}