二、Dialog的消失
1、dismiss
private final Runnable mDismissAction = this::dismissDialog;
public void dismiss() {
if (Looper.myLooper() == mHandler.getLooper()) {
dismissDialog();
} else {
mHandler.post(mDismissAction);
}
}
保证UI操作都在主线程执行，而且引用了Java8新特性写法this::dismissDialog，最后都会调用dismissDialog()
2、dismissDialog
void dismissDialog() {
if (mDecor == null || !mShowing) {
return;
}
if (mWindow.isDestroyed()) {
Log.e(TAG, "Tried to dismissDialog() but the Dialog's window was already destroyed!");
return;
}
try {
//这里移除DecorView
mWindowManager.removeViewImmediate(mDecor);
} finally {
if (mActionMode != null) {
mActionMode.finish();
}
mDecor = null;
mWindow.closeAllPanels();
onStop();
mShowing = false;
sendDismissMessage();
}
}
从show中知道，我们将DecorView加入到WindowManager中去，所以这里移除的是DecorView
3、WindowManagerImpl.removeViewImmediate
public void removeViewImmediate(View view) {
//委托给mGlobal来进行实现
mGlobal.removeView(view, true);
}
同样的交给WindowManagerGlobal去处理
4、WindowManagerGlobal.removeView
public void removeView(View view, boolean immediate) {
if (view == null) {
throw new IllegalArgumentException("view must not be null");
}
synchronized (mLock) {
//待remove view的索引
int index = findViewLocked(view, true);
//mRoots保存着每一个viewRootImpl对象
View curView = mRoots.get(index).getView();
//真正对view进行了remove操作
removeViewLocked(index, immediate);
if (curView == view) {
return;
}
throw new IllegalStateException("Calling with view " + view
+ " but the ViewAncestor is attached to " + curView);
}
}
找到对应要移除的View后进行View逻辑处理工作
5、WindowManagerGlobal.removeViewLocked
private void removeViewLocked(int index, boolean immediate) {
ViewRootImpl root = mRoots.get(index);
View view = root.getView();
if (view != null) {
InputMethodManager imm = InputMethodManager.getInstance();
if (imm != null) {
imm.windowDismissed(mViews.get(index).getWindowToken());
}
}
//重点在ViewRootImpl中的die方法中
boolean deferred = root.die(immediate);
if (view != null) {
view.assignParent(null);
if (deferred) {
mDyingViews.add(view);
}
}
}
找到对应的ViewRootImpl，进行移除并释放工作
6、ViewRootImpl.die
boolean die(boolean immediate) {
if (immediate && !mIsInTraversal) {
//继续跟踪
doDie();
return false;
}
if (!mIsDrawing) {
destroyHardwareRenderer();
} else {
Log.e(TAG, "Attempting to destroy the window while drawing!\n" +
" window=" + this + ", title=" + mWindowAttributes.getTitle());
}
mHandler.sendEmptyMessage(MSG_DIE);
return true;
}
7、ViewRootImpl.doDie
void doDie() {
checkThread();
if (LOCAL_LOGV) Log.v(TAG, "DIE in " + this + " of " + mSurface);
synchronized (this) {
if (mRemoved) {
return;
}
mRemoved = true;
if (mAdded) {
//这里是真正移除Dialog的View
dispatchDetachedFromWindow();
}
if (mAdded && !mFirst) {
//硬件渲染destroy
destroyHardwareRenderer();
if (mView != null) {
int viewVisibility = mView.getVisibility();
boolean viewVisibilityChanged = mViewVisibility != viewVisibility;
if (mWindowAttributesChanged || viewVisibilityChanged) {
// If layout params have been changed, first give them
// to the window manager to make sure it has the correct
// animation info.
try {
if ((relayoutWindow(mWindowAttributes, viewVisibility, false)
& WindowManagerGlobal.RELAYOUT_RES_FIRST_TIME) != 0) {
mWindowSession.finishDrawing(mWindow);
}
} catch (RemoteException e) {
}
}
//Surface的释放
mSurface.release();
}
}
mAdded = false;
}
//移除之前存储的变量
WindowManagerGlobal.getInstance().doRemoveView(this);
}
保证线程安全后，做移除和释放工作
8、WindowManagerGlobal.doRemoveView
一般程序最后的工作都是释放工作，移除之前存储的变量
void doRemoveView(ViewRootImpl root) {
synchronized (mLock) {
final int index = mRoots.indexOf(root);
if (index >= 0) {
//释放工作
mRoots.remove(index);
mParams.remove(index);
final View view = mViews.remove(index);
mDyingViews.remove(view);
}
}
if (HardwareRenderer.sTrimForeground && HardwareRenderer.isAvailable()) {
doTrimForeground();
}
}
9、ViewRootImpl.dispatchDetachedFromWindow
void dispatchDetachedFromWindow() {
if (mView != null && mView.mAttachInfo != null) {
mAttachInfo.mTreeObserver.dispatchOnWindowAttachedChange(false);
//此方法会回调onDetachedFromWindow方法，会做资源的回收
mView.dispatchDetachedFromWindow();
}
mAccessibilityInteractionConnectionManager.ensureNoConnection();
mAccessibilityManager.removeAccessibilityStateChangeListener(
mAccessibilityInteractionConnectionManager);
mAccessibilityManager.removeHighTextContrastStateChangeListener(
mHighContrastTextManager);
removeSendWindowContentChangedCallback();
destroyHardwareRenderer();
setAccessibilityFocus(null, null);
mView.assignParent(null);
mView = null;
mAttachInfo.mRootView = null;
mSurface.release();
if (mInputQueueCallback != null && mInputQueue != null) {
mInputQueueCallback.onInputQueueDestroyed(mInputQueue);
mInputQueue.dispose();
mInputQueueCallback = null;
mInputQueue = null;
}
if (mInputEventReceiver != null) {
mInputEventReceiver.dispose();
mInputEventReceiver = null;
}
try {
//这里调用了mWindowSession的remove方法，在WindowManagerService层通过IPC机制完成真正的window删除
mWindowSession.remove(mWindow);
} catch (RemoteException e) {
}
// Dispose the input channel after removing the window so the Window Manager
// doesn't interpret the input channel being closed as an abnormal termination.
if (mInputChannel != null) {
mInputChannel.dispose();
mInputChannel = null;
}
mDisplayManager.unregisterDisplayListener(mDisplayListener);
unscheduleTraversals();
}
到最后会和添加View的时候完成闭环，还是通过WindowSession的IPC机制去调用的，最后在WindowManagerService层通过IPC机制去实现的
总结
1.Dialog的dismiss和show形成闭环，调用的过程是相似的，只不过多了资源的释放环节
DialogFragment
DialogFragment本身继承自Fragment
public class DialogFragment extends Fragment
implements DialogInterface.OnCancelListener, DialogInterface.OnDismissListener
在平时中，我们需要自定义WeDialogFragment，而且在正式开发中踩过的坑：
- 需要对参数进行onSaveInstanceState操作，这类操作主要是防止异步吊起DialogFragment报nullPoint的Bug
- 需要重写show()，对show做一层弹出时候的保护，这类操作主要是防止异步吊起DialogFragment报onSaveInstanceState的Bug
public class WeDialogFragment extends DialogFragment {
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
Bundle bundle = new Bundle();
bundle.putString(BUNDLE_TITLE, title);
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setStyle(DialogFragment.STYLE_NO_TITLE, R.style.WeDialog);
if (savedInstanceState != null) {
title = savedInstanceState.getString(BUNDLE_TITLE);
}
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
Dialog dialog = super.onCreateDialog(savedInstanceState);
dialog.setCanceledOnTouchOutside(true);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.getWindow().setWindowAnimations(R.style.DialogAnimation);
dialog.getWindow().setBackgroundDrawableResource(android.R.color.transparent);
return dialog;
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
@Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.view_fragment_dialog, container, false);
}
@Override
public void show(FragmentManager manager, String tag) {
if (!manager.isStateSaved()) {
super.show(manager, tag);
}
}
}
然后在Activity中弹出DialogFragment
WeDialogFragment weDialogFragment = new WeDialogFragment();
weDialogFragment.show(activity.getSupportFragmentManager(),"weDialogFragment");
一、DialogFragment的显示
1、DialogFragment.show
public void show(FragmentManager manager, String tag) {
mDismissed = false;
mShownByMe = true;
FragmentTransaction ft = manager.beginTransaction();
ft.add(this, tag);
ft.commit();
}
show的方法其实就是对Fragment的处理，将Fragment添加到Fragment栈中
二、DialogFragment的隐藏
1、DialogFragment.dismiss
public void dismiss() {
dismissInternal(false);
}
public void dismissAllowingStateLoss() {
dismissInternal(true);
}
void dismissInternal(boolean allowStateLoss) {
if (mDismissed) {
return;
}
mDismissed = true;
mShownByMe = false;
if (mDialog != null) {
mDialog.dismiss();
}
mViewDestroyed = true;
if (mBackStackId >= 0) {
getFragmentManager().popBackStack(mBackStackId,
FragmentManager.POP_BACK_STACK_INCLUSIVE);
mBackStackId = -1;
} else {
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.remove(this);
if (allowStateLoss) {
ft.commitAllowingStateLoss();
} else {
ft.commit();
}
}
}
dismiss的方法也是对Fragment的处理，将Fragment移除到Fragment栈中
三、Dialog的创建
1、DialogFragment.onCreateDialog
@NonNull
public Dialog onCreateDialog(Bundle savedInstanceState) {
return new Dialog(getActivity(), getTheme());
}
和创建普通的Dialog没什么区别，我们重写该方法，可以自定义弹出AlertDialog等其他自定义Dialog
四、Dialog的视图
1、DialogFragment.onActivityCreated
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if (!mShowsDialog) {
return;
}
//拿到的就是onCreateView返回值的view对象，具体可以在Fragment源码找到
View view = getView();
if (view != null) {
if (view.getParent() != null) {
throw new IllegalStateException(
"DialogFragment can not be attached to a container view");
}
//真正设置view
mDialog.setContentView(view);
}
final Activity activity = getActivity();
if (activity != null) {
mDialog.setOwnerActivity(activity);
}
mDialog.setCancelable(mCancelable);
mDialog.setOnCancelListener(this);
mDialog.setOnDismissListener(this);
if (savedInstanceState != null) {
Bundle dialogState = savedInstanceState.getBundle(SAVED_DIALOG_STATE_TAG);
if (dialogState != null) {
mDialog.onRestoreInstanceState(dialogState);
}
}
}
在Activity创建的时候，Fragment的周期会回调onActivityCreated，从而对Dialog设置视图
五、Dialog的显示隐藏
Dialog显示隐藏就简单了，随着Fragment的生命周期显示和隐藏，直接看代码就行了
@Override
public void onStart() {
super.onStart();
if (mDialog != null) {
mViewDestroyed = false;
mDialog.show();
}
}
@Override
public void onStop() {
super.onStop();
if (mDialog != null) {
mDialog.hide();
}
}
总结
DialogFragment = Fragment + Dialog，DialogFragment本身继承Fragment，Fragment只是用来依附在Activity上，可以监听Activity的生命周期，从而去通知Dialog做对应的操作，而Dialog才是我们正在显示在屏幕上的弹窗，而非一个Fragment。这里的Dialog真正显示出来的View是从onCreateView()中获取view后，在源码中调用dialog的setContentView()显示出来的