WMS: Apply DecorView window to add layout
android12-release
1. Apply to add layout
At
onCreate
the time,setContentView()
setlayoutResID
(xml layout file), and finally callPhoneWindow.java#setContentView()
2. DecorView initialization
If
mDecor
itDecorView
does not exist, create oneDecorView
; if itmContentParent
does not exist, usemDecor
mContentParent to create
ViewGroup contentParent = (ViewGroup)findViewById(ID_ANDROID_CONTENT)
one ,ID_ANDROID_CONTENT = com.android.internal.R.id.content
so it is just a sub-View. Setting layout is added onandroid.R.id.content
DecorView
mContentParent
DecorView
setContentView()
layoutResID
mContentParent
3. LayoutInflater parses the layout xml file
rInflateChildren()与rInflate()
Loop through layers of xml parsing and add corresponding Views
public View inflate(@LayoutRes int resource, @Nullable ViewGroup root, boolean attachToRoot) {
final Resources res = getContext().getResources();
if (DEBUG) {
Log.d(TAG, "INFLATING from resource: \"" + res.getResourceName(resource) + "\" ("
+ Integer.toHexString(resource) + ")");
}
View view = tryInflatePrecompiled(resource, res, root, attachToRoot);
if (view != null) {
return view;
}
XmlResourceParser parser = res.getLayout(resource);
try {
return inflate(parser, root, attachToRoot);
} finally {
parser.close();
}
}
public View inflate(XmlPullParser parser, @Nullable ViewGroup root, boolean attachToRoot) {
synchronized (mConstructorArgs) {
Trace.traceBegin(Trace.TRACE_TAG_VIEW, "inflate");
final Context inflaterContext = mContext;
final AttributeSet attrs = Xml.asAttributeSet(parser);
Context lastContext = (Context) mConstructorArgs[0];
mConstructorArgs[0] = inflaterContext;
View result = root;
try {
advanceToRootNode(parser);
final String name = parser.getName();
if (DEBUG) {
System.out.println("**************************");
System.out.println("Creating root view: "
+ name);
System.out.println("**************************");
}
if (TAG_MERGE.equals(name)) {
if (root == null || !attachToRoot) {
throw new InflateException("<merge /> can be used only with a valid "
+ "ViewGroup root and attachToRoot=true");
}
rInflate(parser, root, inflaterContext, attrs, false);
} else {
// Temp is the root view that was found in the xml
final View temp = createViewFromTag(root, name, inflaterContext, attrs);
ViewGroup.LayoutParams params = null;
if (root != null) {
if (DEBUG) {
System.out.println("Creating params from root: " +
root);
}
// Create layout params that match root, if supplied
params = root.generateLayoutParams(attrs);
if (!attachToRoot) {
// Set the layout params for temp if we are not
// attaching. (If we are, we use addView, below)
temp.setLayoutParams(params);
}
}
if (DEBUG) {
System.out.println("-----> start inflating children");
}
// Inflate all children under temp against its context.
rInflateChildren(parser, temp, attrs, true);
if (DEBUG) {
System.out.println("-----> done inflating children");
}
// We are supposed to attach all the views we found (int temp)
// to root. Do that now.
if (root != null && attachToRoot) {
root.addView(temp, params);
}
// Decide whether to return the root that was passed in or the
// top view found in xml.
if (root == null || !attachToRoot) {
result = temp;
}
}
} catch (XmlPullParserException e) {
final InflateException ie = new InflateException(e.getMessage(), e);
ie.setStackTrace(EMPTY_STACK_TRACE);
throw ie;
} catch (Exception e) {
final InflateException ie = new InflateException(
getParserStateDescription(inflaterContext, attrs)
+ ": " + e.getMessage(), e);
ie.setStackTrace(EMPTY_STACK_TRACE);
throw ie;
} finally {
// Don't retain static reference on context.
mConstructorArgs[0] = lastContext;
mConstructorArgs[1] = null;
Trace.traceEnd(Trace.TRACE_TAG_VIEW);
}
return result;
}
}
final void rInflateChildren(XmlPullParser parser, View parent, AttributeSet attrs,
boolean finishInflate) throws XmlPullParserException, IOException {
rInflate(parser, parent, parent.getContext(), attrs, finishInflate);
}
void rInflate(XmlPullParser parser, View parent, Context context,
AttributeSet attrs, boolean finishInflate) throws XmlPullParserException, IOException {
final int depth = parser.getDepth();
int type;
boolean pendingRequestFocus = false;
while (((type = parser.next()) != XmlPullParser.END_TAG ||
parser.getDepth() > depth) && type != XmlPullParser.END_DOCUMENT) {
if (type != XmlPullParser.START_TAG) {
continue;
}
final String name = parser.getName();
if (TAG_REQUEST_FOCUS.equals(name)) {
pendingRequestFocus = true;
consumeChildElements(parser);
} else if (TAG_TAG.equals(name)) {
parseViewTag(parser, parent, attrs);
} else if (TAG_INCLUDE.equals(name)) {
if (parser.getDepth() == 0) {
throw new InflateException("<include /> cannot be the root element");
}
parseInclude(parser, context, parent, attrs);
} else if (TAG_MERGE.equals(name)) {
throw new InflateException("<merge /> must be the root element");
} else {
final View view = createViewFromTag(parent, name, context, attrs);
final ViewGroup viewGroup = (ViewGroup) parent;
final ViewGroup.LayoutParams params = viewGroup.generateLayoutParams(attrs);
rInflateChildren(parser, view, attrs, true);
viewGroup.addView(view, params);
}
}
if (pendingRequestFocus) {
parent.restoreDefaultFocus();
}
if (finishInflate) {
parent.onFinishInflate();
}
}
4. ViewGroup adds sub-View
View[] mChildren
: Store child node View,ARRAY_CAPACITY_INCREMENT = 12
12-node expansionmChildrenCount
: The number of valid children in the mChildren array, the remaining items should be null or not considered children
public void addView(View child, int index, LayoutParams params) {
if (DBG) {
System.out.println(this + " addView");
}
if (child == null) {
throw new IllegalArgumentException("Cannot add a null child view to a ViewGroup");
}
// addViewInner() will call child.requestLayout() when setting the new LayoutParams
// therefore, we call requestLayout() on ourselves before, so that the child's request
// will be blocked at our level
requestLayout();
invalidate(true);
addViewInner(child, index, params, false);
}
private void addViewInner(View child, int index, LayoutParams params,
boolean preventRequestLayout) {
if (mTransition != null) {
// Don't prevent other add transitions from completing, but cancel remove
// transitions to let them complete the process before we add to the container
mTransition.cancel(LayoutTransition.DISAPPEARING);
}
if (child.getParent() != null) {
throw new IllegalStateException("The specified child already has a parent. " +
"You must call removeView() on the child's parent first.");
}
if (mTransition != null) {
mTransition.addChild(this, child);
}
if (!checkLayoutParams(params)) {
params = generateLayoutParams(params);
}
if (preventRequestLayout) {
child.mLayoutParams = params;
} else {
child.setLayoutParams(params);
}
if (index < 0) {
index = mChildrenCount;
}
addInArray(child, index);
// tell our children
if (preventRequestLayout) {
child.assignParent(this);
} else {
child.mParent = this;
}
if (child.hasUnhandledKeyListener()) {
incrementChildUnhandledKeyListeners();
}
final boolean childHasFocus = child.hasFocus();
if (childHasFocus) {
requestChildFocus(child, child.findFocus());
}
AttachInfo ai = mAttachInfo;
if (ai != null && (mGroupFlags & FLAG_PREVENT_DISPATCH_ATTACHED_TO_WINDOW) == 0) {
boolean lastKeepOn = ai.mKeepScreenOn;
ai.mKeepScreenOn = false;
child.dispatchAttachedToWindow(mAttachInfo, (mViewFlags&VISIBILITY_MASK));
if (ai.mKeepScreenOn) {
needGlobalAttributesUpdate(true);
}
ai.mKeepScreenOn = lastKeepOn;
}
if (child.isLayoutDirectionInherited()) {
child.resetRtlProperties();
}
dispatchViewAdded(child);
if ((child.mViewFlags & DUPLICATE_PARENT_STATE) == DUPLICATE_PARENT_STATE) {
mGroupFlags |= FLAG_NOTIFY_CHILDREN_ON_DRAWABLE_STATE_CHANGE;
}
if (child.hasTransientState()) {
childHasTransientStateChanged(child, true);
}
if (child.getVisibility() != View.GONE) {
notifySubtreeAccessibilityStateChangedIfNeeded();
}
if (mTransientIndices != null) {
final int transientCount = mTransientIndices.size();
for (int i = 0; i < transientCount; ++i) {
final int oldIndex = mTransientIndices.get(i);
if (index <= oldIndex) {
mTransientIndices.set(i, oldIndex + 1);
}
}
}
if (mCurrentDragStartEvent != null && child.getVisibility() == VISIBLE) {
notifyChildOfDragStart(child);
}
if (child.hasDefaultFocus()) {
// When adding a child that contains default focus, either during inflation or while
// manually assembling the hierarchy, update the ancestor default-focus chain.
setDefaultFocus(child);
}
touchAccessibilityNodeProviderIfNeeded(child);
}
private void addInArray(View child, int index) {
View[] children = mChildren;
final int count = mChildrenCount;
final int size = children.length;
if (index == count) {
if (size == count) {
mChildren = new View[size + ARRAY_CAPACITY_INCREMENT];
System.arraycopy(children, 0, mChildren, 0, size);
children = mChildren;
}
children[mChildrenCount++] = child;
} else if (index < count) {
if (size == count) {
mChildren = new View[size + ARRAY_CAPACITY_INCREMENT];
System.arraycopy(children, 0, mChildren, 0, index);
System.arraycopy(children, index, mChildren, index + 1, count - index);
children = mChildren;
} else {
System.arraycopy(children, index, children, index + 1, count - index);
}
children[index] = child;
mChildrenCount++;
if (mLastTouchDownIndex >= index) {
mLastTouchDownIndex++;
}
} else {
throw new IndexOutOfBoundsException("index=" + index + " count=" + count);
}
}