View的事件分发二

前面说到View的事件分发是从Activity开始的，那是什么传给我们的Activity的呢。

首先我们知道activity只有在onResume后才能点击对吧。

那我们看它的代码，看它和窗口的关系

我们知道Activity里有它实现了一个接口window.Callback

public class Activity extends ContextThemeWrapper        implements LayoutInflater.Factory2,        Window.Callback, KeyEvent.Callback,        OnCreateContextMenuListener, ComponentCallbacks2

   public interface Callback {        /**         * Called to process key events.  At the very least your         * implementation must call         * {@link android.view.Window#superDispatchKeyEvent} to do the         * standard key processing.         *         * @param event The key event.         *         * @return boolean Return true if this event was consumed.         */        public boolean dispatchKeyEvent(KeyEvent event);     //事件分发        /**         * Called to process a key shortcut event.         * At the very least your implementation must call         * {@link android.view.Window#superDispatchKeyShortcutEvent} to do the         * standard key shortcut processing.         *         * @param event The key shortcut event.         * @return True if this event was consumed.         */        public boolean dispatchKeyShortcutEvent(KeyEvent event);        /**         * Called to process touch screen events.  At the very least your         * implementation must call         * {@link android.view.Window#superDispatchTouchEvent} to do the         * standard touch screen processing.         *         * @param event The touch screen event.         *         * @return boolean Return true if this event was consumed.         */        public boolean dispatchTouchEvent(MotionEvent event);        /**         * Called to process trackball events.  At the very least your         * implementation must call         * {@link android.view.Window#superDispatchTrackballEvent} to do the         * standard trackball processing.         *         * @param event The trackball event.         *         * @return boolean Return true if this event was consumed.         */        public boolean dispatchTrackballEvent(MotionEvent event);        /**         * Called to process generic motion events.  At the very least your         * implementation must call         * {@link android.view.Window#superDispatchGenericMotionEvent} to do the         * standard processing.         *         * @param event The generic motion event.         *         * @return boolean Return true if this event was consumed.         */        public boolean dispatchGenericMotionEvent(MotionEvent event);        /**         * Called to process population of {@link AccessibilityEvent}s.         *         * @param event The event.         *         * @return boolean Return true if event population was completed.         */        public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event);        /**         * Instantiate the view to display in the panel for 'featureId'.         * You can return null, in which case the default content (typically         * a menu) will be created for you.         *         * @param featureId Which panel is being created.         *         * @return view The top-level view to place in the panel.         *         * @see #onPreparePanel         */        @Nullable        public View onCreatePanelView(int featureId);        /**         * Initialize the contents of the menu for panel 'featureId'.  This is         * called if onCreatePanelView() returns null, giving you a standard         * menu in which you can place your items.  It is only called once for         * the panel, the first time it is shown.         *         * <p>You can safely hold on to <var>menu</var> (and any items created         * from it), making modifications to it as desired, until the next         * time onCreatePanelMenu() is called for this feature.         *         * @param featureId The panel being created.         * @param menu The menu inside the panel.         *         * @return boolean You must return true for the panel to be displayed;         *         if you return false it will not be shown.         */        public boolean onCreatePanelMenu(int featureId, Menu menu);        /**         * Prepare a panel to be displayed.  This is called right before the         * panel window is shown, every time it is shown.         *         * @param featureId The panel that is being displayed.         * @param view The View that was returned by onCreatePanelView().         * @param menu If onCreatePanelView() returned null, this is the Menu         *             being displayed in the panel.         *         * @return boolean You must return true for the panel to be displayed;         *         if you return false it will not be shown.         *         * @see #onCreatePanelView         */        public boolean onPreparePanel(int featureId, View view, Menu menu);        /**         * Called when a panel's menu is opened by the user. This may also be         * called when the menu is changing from one type to another (for         * example, from the icon menu to the expanded menu).         *         * @param featureId The panel that the menu is in.         * @param menu The menu that is opened.         * @return Return true to allow the menu to open, or false to prevent         *         the menu from opening.         */        public boolean onMenuOpened(int featureId, Menu menu);        /**         * Called when a panel's menu item has been selected by the user.         *         * @param featureId The panel that the menu is in.         * @param item The menu item that was selected.         *         * @return boolean Return true to finish processing of selection, or         *         false to perform the normal menu handling (calling its         *         Runnable or sending a Message to its target Handler).         */        public boolean onMenuItemSelected(int featureId, MenuItem item);        /**         * This is called whenever the current window attributes change.         *         */        public void onWindowAttributesChanged(WindowManager.LayoutParams attrs);        /**         * This hook is called whenever the content view of the screen changes         * (due to a call to         * {@link Window#setContentView(View, android.view.ViewGroup.LayoutParams)         * Window.setContentView} or         * {@link Window#addContentView(View, android.view.ViewGroup.LayoutParams)         * Window.addContentView}).         */        public void onContentChanged();        /**         * This hook is called whenever the window focus changes.  See         * {@link View#onWindowFocusChanged(boolean)         * View.onWindowFocusChangedNotLocked(boolean)} for more information.         *         * @param hasFocus Whether the window now has focus.         */        public void onWindowFocusChanged(boolean hasFocus);        /**         * Called when the window has been attached to the window manager.         * See {@link View#onAttachedToWindow() View.onAttachedToWindow()}         * for more information.         */        public void onAttachedToWindow();        /**         * Called when the window has been attached to the window manager.         * See {@link View#onDetachedFromWindow() View.onDetachedFromWindow()}         * for more information.         */        public void onDetachedFromWindow();        /**         * Called when a panel is being closed.  If another logical subsequent         * panel is being opened (and this panel is being closed to make room for the subsequent         * panel), this method will NOT be called.         *         * @param featureId The panel that is being displayed.         * @param menu If onCreatePanelView() returned null, this is the Menu         *            being displayed in the panel.         */        public void onPanelClosed(int featureId, Menu menu);        /**         * Called when the user signals the desire to start a search.         *         * @return true if search launched, false if activity refuses (blocks)         *         * @see android.app.Activity#onSearchRequested()         */        public boolean onSearchRequested();        /**         * Called when an action mode is being started for this window. Gives the         * callback an opportunity to handle the action mode in its own unique and         * beautiful way. If this method returns null the system can choose a way         * to present the mode or choose not to start the mode at all.         *         * @param callback Callback to control the lifecycle of this action mode         * @return The ActionMode that was started, or null if the system should present it         */        @Nullable        public ActionMode onWindowStartingActionMode(ActionMode.Callback callback);        /**         * Called when an action mode has been started. The appropriate mode callback         * method will have already been invoked.         *         * @param mode The new mode that has just been started.         */        public void onActionModeStarted(ActionMode mode);        /**         * Called when an action mode has been finished. The appropriate mode callback         * method will have already been invoked.         *         * @param mode The mode that was just finished.         */        public void onActionModeFinished(ActionMode mode);    }

里面有很多我们耳熟能详的方法，如onWindowsfocusChanged,看到了没，还有我们的onDispatchTouchEvent吧。接口被定义在window里，说明肯定是类似phonewindow的那种对象来回调activity.

mWindow = PolicyManager.makeNewWindow(this);mWindow.setCallback(this);

Activity的attach方法里出现了如上代码。

总结几点View分发一的文章得出的结论，

由于onIntercept里可以根据事件而返回。

1.当父容器拦截了down事件后，mfirstTouch为空，所以就以父容器拦截整个事件结束，

2.当父容器不拦截down事件，子容器如果消耗掉的down事件的化，此时mFirstTouch不为空还是进入语句，这个事件的move和up还是得经过父容器的拦截器，它的事件还是可能被父容器拦截

3.当父容器不拦截down事件，子容器也不去消耗，这个事件就是以父容器上传给activity而结束。

上面情况是不考虑一个标志，这个标志称为不准拦截标志。