View the loading process was from the activity of setcontentView () begin to see how View is loaded.
/**
* Set the activity content from a layout resource. The resource will be
* inflated, adding all top-level views to the activity.
*
* @param layoutResID Resource ID to be inflated.
*
* @see #setContentView(android.view.View)
* @see #setContentView(android.view.View, android.view.ViewGroup.LayoutParams)
*/
public void setContentView(@LayoutRes int layoutResID) {
getWindow().setContentView(layoutResID);
initWindowDecorActionBar();
}In the activity of setContentView () is called in getWindow (). SetContentView (layoutResID).
/**
* Retrieve the current {@link android.view.Window} for the activity.
* This can be used to directly access parts of the Window API that
* are not available through Activity/Screen.
*
* @return Window The current window, or null if the activity is not
* visual.
*/
public Window getWindow() {
return mWindow;
}
Returns a window, found window is an abstract class.
We continue to look for mwindow is another activity that assignment in the source code.
final void attach(Context context, ActivityThread aThread,
Instrumentation instr, IBinder token, int ident,
Application application, Intent intent, ActivityInfo info,
CharSequence title, Activity parent, String id,
NonConfigurationInstances lastNonConfigurationInstances,
Configuration config, String referrer, IVoiceInteractor voiceInteractor) {
attachBaseContext(context);
mFragments.attachHost(null /*parent*/);
mWindow = new PhoneWindow(this);
mWindow.setCallback(this);
mWindow.setOnWindowDismissedCallback(this);
mWindow.getLayoutInflater().setPrivateFactory(this);
if (info.softInputMode != WindowManager.LayoutParams.SOFT_INPUT_STATE_UNSPECIFIED) {
mWindow.setSoftInputMode(info.softInputMode);
}
if (info.uiOptions != 0) {
mWindow.setUiOptions(info.uiOptions);
}
mUiThread = Thread.currentThread();
Found that the window is PhoneWindow, then go to PhoneWindow in setcontentView () method
@Override
public void setContentView(int layoutResID) {
// Note: FEATURE_CONTENT_TRANSITIONS may be set in the process of installing the window
// decor, when theme attributes and the like are crystalized. Do not check the feature
// before this happens.
if (mContentParent == null) {
installDecor();
} else if (!hasFeature(FEATURE_CONTENT_TRANSITIONS)) {
mContentParent.removeAllViews();
}
if (hasFeature(FEATURE_CONTENT_TRANSITIONS)) {
final Scene newScene = Scene.getSceneForLayout(mContentParent, layoutResID,
getContext());
transitionTo(newScene);
} else {
mLayoutInflater.inflate(layoutResID, mContentParent);
}
mContentParent.requestApplyInsets();
final Callback cb = getCallback();
if (cb != null && !isDestroyed()) {
cb.onContentChanged();
}
}
@Override
public void setContentView(View view) {
setContentView(view, new ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT));
}
@Override
public void setContentView(View view, ViewGroup.LayoutParams params) {
// Note: FEATURE_CONTENT_TRANSITIONS may be set in the process of installing the window
// decor, when theme attributes and the like are crystalized. Do not check the feature
// before this happens.
if (mContentParent == null) {
installDecor();
} else if (!hasFeature(FEATURE_CONTENT_TRANSITIONS)) {
mContentParent.removeAllViews();
}
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();
}
}
Although phoneWindow three setContentView () method, but the last three logical method is basically the same. Continue down
IF (mContentParent == null) {
installDecor ();
}
Here is determined, we look at what is mContentParent
// This is the view in which the window contents are placed. It is either
// mDecor itself, or a child of mDecor where the contents go.
private ViewGroup mContentParent;
Means that our activity layout .xml top ViewGroup, and so will be able to verify below. InstallDecor here ();
private void installDecor() {
if (mDecor == null) {
mDecor = generateDecor();
mDecor.setDescendantFocusability(ViewGroup.FOCUS_AFTER_DESCENDANTS);
mDecor.setIsRootNamespace(true);
if (!mInvalidatePanelMenuPosted && mInvalidatePanelMenuFeatures != 0) {
mDecor.postOnAnimation(mInvalidatePanelMenuRunnable);
}
}
if (mContentParent == null) {
mContentParent = generateLayout(mDecor);
// Set up decor part of UI to ignore fitsSystemWindows if appropriate.
mDecor.makeOptionalFitsSystemWindows();
。。。。。。mDecor = generateDecor();
protected DecorView generateDecor() {
return new DecorView(getContext(), -1);
}Here the meaning is created DecorView
// This is the top-level view of the window, containing the window decor.
private DecorView mDecor;
Here that DecorView is the top view window, including the window decoration. DecorView is Shane
private final class DecorView extends FrameLayout implements RootViewSurfaceTaker {
/* package */int mDefaultOpacity = PixelFormat.OPAQUE;
/** The feature ID of the panel, or -1 if this is the application's DecorView */
private final int mFeatureId;
private final Rect mDrawingBounds = new Rect();
DecorView is PhoneWindow internal class, it is integrated FrameLayout. So conclusion DecorView is the topmost window view, it is a FrameLayout.
Continue to look installDecor () in
IF (mContentParent == null) {
mContentParent = generateLayout (mDecor);
Take a look at generateLayout () methods did what
protected ViewGroup generateLayout(DecorView decor) {
// Apply data from current theme.
TypedArray a = getWindowStyle();
if (false) {
System.out.println("From style:");
String s = "Attrs:";
for (int i = 0; i < R.styleable.Window.length; i++) {
s = s + " " + Integer.toHexString(R.styleable.Window[i]) + "="
+ a.getString(i);
}
System.out.println(s);
}
mIsFloating = a.getBoolean(R.styleable.Window_windowIsFloating, false);
int flagsToUpdate = (FLAG_LAYOUT_IN_SCREEN|FLAG_LAYOUT_INSET_DECOR)
& (~getForcedWindowFlags());
if (mIsFloating) {
setLayout(WRAP_CONTENT, WRAP_CONTENT);
setFlags(0, flagsToUpdate);
} else {
setFlags(FLAG_LAYOUT_IN_SCREEN|FLAG_LAYOUT_INSET_DECOR, flagsToUpdate);
}
if (a.getBoolean(R.styleable.Window_windowNoTitle, false)) {
requestFeature(FEATURE_NO_TITLE);
} else if (a.getBoolean(R.styleable.Window_windowActionBar, false))
。。。。。。
This method is particularly long, the way to do a lot of work, first set DecorView style based on theme style settings, set titlebar, followed by sub-View is DecorView, and here the child View is mContentParent mentioned above, set FEATURE_NO_ACTIONBAR, then DecorView only mContentParent a sub-View, which explains the above question: mContentParent is a sub-element of DecorView itself or DecorView. DecorView contains two elements: titlebar and mContentParent.
Summary:
Each activity corresponds to a Window, which is PhoneWindow, DecorView is the top of the layout PhoneWindow, DecorView is FrameLayout, DecorView consists of two parts titlebar and mContentParent, this activity is mContentParent the corresponding layout file.
When loaded from oncreate inside setContentView activity of (), then call the phonewindow of
setContentView (). SetContentView created in DecorView and mContentParent, mContentParent is Viewgroup, style content and application activity layout xml file mContentParent loaded. mContentParent added to DecorView in DecorView successfully created after DecorView loaded into the activity of the Window, so the interface will load complete.
