Android Window、PhoneWindow、Activity学习心得第二弹
Window 分析
这里先给出部分源码
目录（Android 4.4/frameworks/base/core/java/android/view/Window.java）
public abstract class Window {
public static final int FEATURE_OPTIONS_PANEL = 0;
public static final int FEATURE_NO_TITLE = 1;
.......
public static final int FEATURE_CONTEXT_MENU = 6;
public static final int FEATURE_CUSTOM_TITLE = 7;
public static final int FEATURE_ACTION_BAR = 8;
public static final int FEATURE_ACTION_BAR_OVERLAY = 9;
.......
public interface Callback {
.....
public boolean dispatchKeyEvent(KeyEvent event);
......
public boolean dispatchTouchEvent(MotionEvent event);
.....
public boolean dispatchGenericMotionEvent(MotionEvent event);
....
public View onCreatePanelView(int featureId);
....
public boolean onMenuItemSelected(int featureId, MenuItem item);
.....
public void onWindowAttributesChanged(WindowManager.LayoutParams attrs);
public void onContentChanged();
public void onWindowFocusChanged(boolean hasFocus);
public void onAttachedToWindow();
public void onDetachedFromWindow();
public void onPanelClosed(int featureId, Menu menu);
public boolean onSearchRequested();
public ActionMode onWindowStartingActionMode(ActionMode.Callback callback);
public void onActionModeStarted(ActionMode mode);
public void onActionModeFinished(ActionMode mode);
}
public void setCallback(Callback callback) {
mCallback = callback;
}
public void setFlags(int flags, int mask) {
final WindowManager.LayoutParams attrs = getAttributes();
attrs.flags = (attrs.flags&~mask) | (flags&mask);
if ((mask&WindowManager.LayoutParams.FLAG_NEEDS_MENU_KEY) != 0) {
attrs.privateFlags |= WindowManager.LayoutParams.PRIVATE_FLAG_SET_NEEDS_MENU_KEY;
}
mForcedWindowFlags |= mask;
if (mCallback != null) {
mCallback.onWindowAttributesChanged(attrs);
}
}
public boolean requestFeature(int featureId) {
final int flag = 1<<featureId;
mFeatures |= flag;
mLocalFeatures |= mContainer != null ? (flag&~mContainer.mFeatures) : flag;
return (mFeatures&flag) != 0;
}
public View findViewById(int id) {
return getDecorView().findViewById(id);
}
public abstract void setContentView(int layoutResID);
public abstract void setTitle(CharSequence title);
public abstract LayoutInflater getLayoutInflater();
}首先，正如我们所知道的通过回调的方式Activity implements Window.Callback
而
Callback主要用来处理
按键事件（dispatchKeyEvent）
触摸事件 （dispatchTouchEvent） 滑动事件（dispatchTrackballEvent）等等一系列事件
设置菜单、ActionMOde、监控内容等一系列动作
正是因为
mWindow = PolicyManager.makeNewWindow(this);
mWindow.setCallback(this);监听回调，所以一系列最终的处理交给了Activity
当然，这里对于处理不做具体分析
接下来，我们看看
Window属性
FEATURE_OPTIONS_PANEL = 0; 功能不明，参见后面的说明(默认使能)
FEATURE_NO_TITLE = 1; 无标题栏
FEATURE_PROGRESS = 2; 在标题栏上显示加载进度，例如webview加载网页时(条状进度条)
FEATURE_LEFT_ICON = 3; 在标题栏左侧显示一个图标
FEATURE_RIGHT_ICON = 4; 在标题栏右侧显示一个图标
FEATURE_INDETERMINATE_PROGRESS = 5; 不确定的进度(圆圈状等待图标)
FEATURE_CONTEXT_MENU = 6; 上下文菜单，相当于PC上的右键菜单(默认使能)
FEATURE_CUSTOM_TITLE = 7; 自定义标题栏，该属性不能与其他标题栏属性合用
FEATURE_OPENGL = 8; 如果开启OpenGL，那么2D将由OpenGL处理(OpenGL中2D是3D的子集)
PROGRESS_VISIBILITY_ON = -1; 进度条可见
PROGRESS_VISIBILITY_OFF = -2; 进度条不可见
PROGRESS_INDETERMINATE_ON = -3; 开启不确定模式
PROGRESS_INDETERMINATE_OFF = -4; 关闭不确定模式
PROGRESS_START = 0; 第一进度条的最小值
PROGRESS_END = 10000; 第一进度条的最大值
PROGRESS_SECONDARY_START = 20000; 第二进度条的最小值
PROGRESS_SECONDARY_END = 30000; 第二进度条的最大值
这些 Feature 和 Flag 有什么用呢,其实很明显他们决定了我们Activity外貌（风格和样式）
那么，接下来我们就来看看Window的具体实现类PhoneWindow
目录（Android 4.4/frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindow.java）
public class PhoneWindow extends Window implements MenuBuilder.Callback {
......
public PhoneWindow(Context context) {
super(context);
mLayoutInflater = LayoutInflater.from(context);
}
.....
}还记得我们第一弹中给出的关于Window、PhoneWindow、DecorView的关系图吗，这里我们稍作回顾
同样，我们知道
知道，每一个应用程序窗口的视图对象都有一个关联的ViewRoot对象，这些关联关系是由窗口管理器来维护的
简单来说，ViewRoot相当于是MVC模型中的Controller，它有以下职责：
1. 负责为应用程序窗口视图创建Surface。
2. 配合WindowManagerService来管理系统的应用程序窗口。
3. 负责管理、布局和渲染应用程序窗口视图的UI。
既然如此，那么接下来我们便开始构建视图UI
例如：我们创建自己的Activity，并在其中写道
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
}同样我们跟踪发现
public class Activity extends ContextThemeWrapper
implements LayoutInflater.Factory,
Window.Callback, KeyEvent.Callback,
OnCreateContextMenuListener, ComponentCallbacks {
......
private Window mWindow;
......
public Window getWindow() {
return mWindow;
}
......
public final boolean requestWindowFeature(int featureId) {
return getWindow().requestFeature(featureId);
}
public void setContentView(int layoutResID) {
getWindow().setContentView(layoutResID);
}
......
} 他们最终交给了PhoneWindow（Window）处理
同样在PhoneWindow中
public class PhoneWindow extends Window implements MenuBuilder.Callback {
......
// 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;
......
public boolean requestFeature(int featureId) {
//这里 requestFeature 必须在 setContentView之前
if (mContentParent != null) {
throw new AndroidRuntimeException("requestFeature() must be called before adding content");
}
final int features = getFeatures();
//最终在Window中处理
return super.requestFeature(featureId);
}
@Override
public void setContentView(int layoutResID) {
if (mContentParent == null) {
installDecor();
} else {
mContentParent.removeAllViews();
}
mLayoutInflater.inflate(layoutResID, mContentParent);
final Callback cb = getCallback();
if (cb != null) {
cb.onContentChanged();
}
}
......
}
PhoneWindow类的成员变量mContentParent用来描述一个类型为DecorView的视图对象，或者这个类型为DecorView的视图对象的一个子视图对象，用作UI容器。当它的值等于null的时候，就说明正在处理的应用程序窗口的视图对象还没有创建。在这种情况下，就会调用成员函数installDecor来创建应用程序窗口视图对象。否则的话，就说明是要重新设置应用程序窗口的视图。在重新设置之前，首先调用成员变量mContentParent所描述的一个ViewGroup对象来移除原来的UI内空。
由于我们是在Activity组件启动的过程中创建应用程序窗口视图的，因此，我们就假设此时PhoneWindow类的成员变量mContentParent的值等于null。接下来，函数就会调用成员函数installDecor来创建应用程序窗口视图对象，接着再通过调用PhoneWindow类的成员变量mLayoutInflater所描述的一个LayoutInflater对象的成员函数inflate来将参数layoutResID所描述的一个UI布局设置到前面所创建的应用程序窗口视图中去，最后还会调用一个Callback接口的成员函数onContentChanged来通知对应的Activity组件，它的视图内容发生改变了。
那么接下来我们便开始初始化DecorView
public class PhoneWindow extends Window implements MenuBuilder.Callback {
......
// This is the top-level view of the window, containing the window decor.
private DecorView mDecor;
......
// 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;
......
private TextView mTitleView;
......
private CharSequence mTitle = null;
......
private void installDecor() {
if (mDecor == null) {
mDecor = generateDecor();
......
}
if (mContentParent == null) {
mContentParent = generateLayout(mDecor);
mTitleView = (TextView)findViewById(com.android.internal.R.id.title);
if (mTitleView != null) {
if ((getLocalFeatures() & (1 << FEATURE_NO_TITLE)) != 0) {
View titleContainer =
findViewById(com.android.internal.R.id.title_container);
if (titleContainer != null) {
titleContainer.setVisibility(View.GONE);
} else {
mTitleView.setVisibility(View.GONE);
}
if (mContentParent instanceof FrameLayout) {
((FrameLayout)mContentParent).setForeground(null);
}
} else {
mTitleView.setText(mTitle);
}
}
}
}
......
}接下来，我们便开始构建
private final class DecorView extends FrameLayout implements RootViewSurfaceTaker {
......
public DecorView(Context context, int featureId) {
super(context);
mFeatureId = featureId;
}
}
protected DecorView generateDecor() {
return new DecorView(getContext(), -1);
}
protected ViewGroup generateLayout(DecorView decor) {
TypedArray a = getWindowStyle();
mIsFloating = a.getBoolean(com.android.internal.R.styleable.Window_windowIsFloating, false);
mIsTranslucent = a.getBoolean(com.android.internal.R.styleable.Window_windowIsTranslucent, 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(com.android.internal.R.styleable.Window_windowNoTitle, false)) {
requestFeature(FEATURE_NO_TITLE);
} else if (a.getBoolean(com.android.internal.R.styleable.Window_windowActionBar, false)) {
requestFeature(FEATURE_ACTION_BAR);
}
if (a.getBoolean(com.android.internal.R.styleable.Window_windowActionBarOverlay, false)) {
requestFeature(FEATURE_ACTION_BAR_OVERLAY);
}
if (a.getBoolean(com.android.internal.R.styleable.Window_windowActionModeOverlay, false)) {
requestFeature(FEATURE_ACTION_MODE_OVERLAY);
}
if (a.getBoolean(com.android.internal.R.styleable.Window_windowFullscreen, false)) {
setFlags(FLAG_FULLSCREEN, FLAG_FULLSCREEN & (~getForcedWindowFlags()));
}
if (a.getBoolean(com.android.internal.R.styleable.Window_windowTranslucentStatus,
false)) {
setFlags(FLAG_TRANSLUCENT_STATUS, FLAG_TRANSLUCENT_STATUS
& (~getForcedWindowFlags()));
}
if (a.getBoolean(com.android.internal.R.styleable.Window_windowTranslucentNavigation,
false)) {
setFlags(FLAG_TRANSLUCENT_NAVIGATION, FLAG_TRANSLUCENT_NAVIGATION
& (~getForcedWindowFlags()));
}
if (a.getBoolean(com.android.internal.R.styleable.Window_windowOverscan, false)) {
setFlags(FLAG_LAYOUT_IN_OVERSCAN, FLAG_LAYOUT_IN_OVERSCAN&(~getForcedWindowFlags()));
}
if (a.getBoolean(com.android.internal.R.styleable.Window_windowShowWallpaper, false)) {
setFlags(FLAG_SHOW_WALLPAPER, FLAG_SHOW_WALLPAPER&(~getForcedWindowFlags()));
}
if (a.getBoolean(com.android.internal.R.styleable.Window_windowEnableSplitTouch,
getContext().getApplicationInfo().targetSdkVersion
>= android.os.Build.VERSION_CODES.HONEYCOMB)) {
setFlags(FLAG_SPLIT_TOUCH, FLAG_SPLIT_TOUCH&(~getForcedWindowFlags()));
}
a.getValue(com.android.internal.R.styleable.Window_windowMinWidthMajor, mMinWidthMajor);
a.getValue(com.android.internal.R.styleable.Window_windowMinWidthMinor, mMinWidthMinor);
if (a.hasValue(com.android.internal.R.styleable.Window_windowFixedWidthMajor)) {
if (mFixedWidthMajor == null) mFixedWidthMajor = new TypedValue();
a.getValue(com.android.internal.R.styleable.Window_windowFixedWidthMajor,
mFixedWidthMajor);
}
if (a.hasValue(com.android.internal.R.styleable.Window_windowFixedWidthMinor)) {
if (mFixedWidthMinor == null) mFixedWidthMinor = new TypedValue();
a.getValue(com.android.internal.R.styleable.Window_windowFixedWidthMinor,
mFixedWidthMinor);
}
if (a.hasValue(com.android.internal.R.styleable.Window_windowFixedHeightMajor)) {
if (mFixedHeightMajor == null) mFixedHeightMajor = new TypedValue();
a.getValue(com.android.internal.R.styleable.Window_windowFixedHeightMajor,
mFixedHeightMajor);
}
if (a.hasValue(com.android.internal.R.styleable.Window_windowFixedHeightMinor)) {
if (mFixedHeightMinor == null) mFixedHeightMinor = new TypedValue();
a.getValue(com.android.internal.R.styleable.Window_windowFixedHeightMinor,
mFixedHeightMinor);
}
final Context context = getContext();
final int targetSdk = context.getApplicationInfo().targetSdkVersion;
final boolean targetPreHoneycomb = targetSdk < android.os.Build.VERSION_CODES.HONEYCOMB;
final boolean targetPreIcs = targetSdk < android.os.Build.VERSION_CODES.ICE_CREAM_SANDWICH;
final boolean targetHcNeedsOptions = context.getResources().getBoolean(
com.android.internal.R.bool.target_honeycomb_needs_options_menu);
final boolean noActionBar = !hasFeature(FEATURE_ACTION_BAR) || hasFeature(FEATURE_NO_TITLE);
if (targetPreHoneycomb || (targetPreIcs && targetHcNeedsOptions && noActionBar)) {
addFlags(WindowManager.LayoutParams.FLAG_NEEDS_MENU_KEY);
} else {
clearFlags(WindowManager.LayoutParams.FLAG_NEEDS_MENU_KEY);
}
if (mAlwaysReadCloseOnTouchAttr || getContext().getApplicationInfo().targetSdkVersion
>= android.os.Build.VERSION_CODES.HONEYCOMB) {
if (a.getBoolean(
com.android.internal.R.styleable.Window_windowCloseOnTouchOutside,
false)) {
setCloseOnTouchOutsideIfNotSet(true);
}
}
WindowManager.LayoutParams params = getAttributes();
if (!hasSoftInputMode()) {
params.softInputMode = a.getInt(
com.android.internal.R.styleable.Window_windowSoftInputMode,
params.softInputMode);
}
if (a.getBoolean(com.android.internal.R.styleable.Window_backgroundDimEnabled,
mIsFloating)) {
/* All dialogs should have the window dimmed */
if ((getForcedWindowFlags()&WindowManager.LayoutParams.FLAG_DIM_BEHIND) == 0) {
params.flags |= WindowManager.LayoutParams.FLAG_DIM_BEHIND;
}
if (!haveDimAmount()) {
params.dimAmount = a.getFloat(
android.R.styleable.Window_backgroundDimAmount, 0.5f);
}
}
if (params.windowAnimations == 0) {
params.windowAnimations = a.getResourceId(
com.android.internal.R.styleable.Window_windowAnimationStyle, 0);
}
// The rest are only done if this window is not embedded; otherwise,
// the values are inherited from our container.
if (getContainer() == null) {
if (mBackgroundDrawable == null) {
if (mBackgroundResource == 0) {
mBackgroundResource = a.getResourceId(
com.android.internal.R.styleable.Window_windowBackground, 0);
}
if (mFrameResource == 0) {
mFrameResource = a.getResourceId(com.android.internal.R.styleable.Window_windowFrame, 0);
}
if (false) {
System.out.println("Background: "
+ Integer.toHexString(mBackgroundResource) + " Frame: "
+ Integer.toHexString(mFrameResource));
}
}
mTextColor = a.getColor(com.android.internal.R.styleable.Window_textColor, 0xFF000000);
}
// Inflate the window decor.
int layoutResource;
int features = getLocalFeatures();
// System.out.println("Features: 0x" + Integer.toHexString(features));
if ((features & ((1 << FEATURE_LEFT_ICON) | (1 << FEATURE_RIGHT_ICON))) != 0) {
if (mIsFloating) {
TypedValue res = new TypedValue();
getContext().getTheme().resolveAttribute(
com.android.internal.R.attr.dialogTitleIconsDecorLayout, res, true);
layoutResource = res.resourceId;
} else {
layoutResource = com.android.internal.R.layout.screen_title_icons;
}
// XXX Remove this once action bar supports these features.
removeFeature(FEATURE_ACTION_BAR);
// System.out.println("Title Icons!");
} else if ((features & ((1 << FEATURE_PROGRESS) | (1 << FEATURE_INDETERMINATE_PROGRESS))) != 0
&& (features & (1 << FEATURE_ACTION_BAR)) == 0) {
// Special case for a window with only a progress bar (and title).
// XXX Need to have a no-title version of embedded windows.
layoutResource = com.android.internal.R.layout.screen_progress;
// System.out.println("Progress!");
} else if ((features & (1 << FEATURE_CUSTOM_TITLE)) != 0) {
// Special case for a window with a custom title.
// If the window is floating, we need a dialog layout
if (mIsFloating) {
TypedValue res = new TypedValue();
getContext().getTheme().resolveAttribute(
com.android.internal.R.attr.dialogCustomTitleDecorLayout, res, true);
layoutResource = res.resourceId;
} else {
layoutResource = com.android.internal.R.layout.screen_custom_title;
}
// XXX Remove this once action bar supports these features.
removeFeature(FEATURE_ACTION_BAR);
} else if ((features & (1 << FEATURE_NO_TITLE)) == 0) {
// If no other features and not embedded, only need a title.
// If the window is floating, we need a dialog layout
if (mIsFloating) {
TypedValue res = new TypedValue();
getContext().getTheme().resolveAttribute(
com.android.internal.R.attr.dialogTitleDecorLayout, res, true);
layoutResource = res.resourceId;
} else if ((features & (1 << FEATURE_ACTION_BAR)) != 0) {
layoutResource = com.android.internal.R.layout.screen_action_bar;
} else {
layoutResource = com.android.internal.R.layout.screen_title;
}
// System.out.println("Title!");
} else if ((features & (1 << FEATURE_ACTION_MODE_OVERLAY)) != 0) {
layoutResource = com.android.internal.R.layout.screen_simple_overlay_action_mode;
} else {
// Embedded, so no decoration is needed.
layoutResource = com.android.internal.R.layout.screen_simple;
// System.out.println("Simple!");
}
mDecor.startChanging();
Trace.traceBegin(Trace.TRACE_TAG_VIEW, "DecorView-inflate");
View in = mLayoutInflater.inflate(layoutResource, null);
Trace.traceEnd(Trace.TRACE_TAG_VIEW);
//add for Multi window
if (mMultiWindow && !mIsFloating){
if (context.getPackageName().contains("launcher") || mIsTranslucent){
Log.d(TAG, "MW phoneWindow do nothing");
} else {
Log.d(TAG, "MW PhoneWindow decor start ");
in = prepareMultiWindow(context,in);
Log.d(TAG, "MW PhoneWindow decor end ");
}
}
//end
decor.addView(in, new ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT));
ViewGroup contentParent = (ViewGroup)findViewById(ID_ANDROID_CONTENT);
if (contentParent == null) {
throw new RuntimeException("Window couldn't find content container view");
}
if ((features & (1 << FEATURE_INDETERMINATE_PROGRESS)) != 0) {
ProgressBar progress = getCircularProgressBar(false);
if (progress != null) {
progress.setIndeterminate(true);
}
}
//Remaining setup - of background and title - that only applies
//to top-level windows.
if (getContainer() == null) {
Drawable drawable = mBackgroundDrawable;
if (mBackgroundResource != 0) {
drawable = getContext().getResources().getDrawable(mBackgroundResource);
}
mDecor.setWindowBackground(drawable);
drawable = null;
if (mFrameResource != 0) {
drawable = getContext().getResources().getDrawable(mFrameResource);
}
mDecor.setWindowFrame(drawable);
// System.out.println("Text=" + Integer.toHexString(mTextColor) +
// " Sel=" + Integer.toHexString(mTextSelectedColor) +
// " Title=" + Integer.toHexString(mTitleColor));
if (mTitleColor == 0) {
mTitleColor = mTextColor;
}
if (mTitle != null) {
setTitle(mTitle);
}
setTitleColor(mTitleColor);
}
mDecor.finishChanging();
return contentParent;
到了这里，我们依据不同的Feature和Flag 来初始化layout 算是初步完成
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