编程中home键有什么用
的有关信息介绍如下：
android4.0之后应用程序无法再获得Home键消息，这样是对滴，但如果想自己写Launcher就得对Home键相关的一些消息进行处理了。Home消息是在android framwork中处理的，我们找到Home键处理相关的代码(不想细看的可以直接看最后)frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java 中的PhoneWindowManager.java interceptKeyBeforeDispatching 函数中有以下内容 // First we always handle the home key here, so applications // can never break it, although if keyguard is on, we do let // it handle it, because that gives us the correct 5 second // timeout. if (keyCode == KeyEvent.KEYCODE_HOME) { // If we have released the home key, and didn't do anything else // while it was pressed, then it is time to go home! if (mHomePressed && !down) { mHomePressed = false; if (!canceled) { // If an incoming call is ringing, HOME is totally disabled. // (The user is already on the InCallScreen at this point, // and his ONLY options are to answer or reject the call.) boolean incomingRinging = false; try { ITelephony telephonyService = getTelephonyService(); if (telephonyService != null) { incomingRinging = telephonyService.isRinging();//是否正好有电话打进来 } } catch (RemoteException ex) { Log.w(TAG, "RemoteException from getPhoneInterface()", ex); } if (incomingRinging) { Log.i(TAG, "Ignoring HOME; there's a ringing incoming call.");//来电中的时候可以看到 打印个消息就完了 } else { launchHomeFromHotKey();//可以看到这里有launchHome，应该是这里通知了Launcher程序，继续往下看 } } else { Log.i(TAG, "Ignoring HOME; event canceled."); } return -1; }// If a system window has focus, then it doesn't make sense // right now to interact with applications. //这一段没有看的很明白，不过很明显没有对Home键处理，只是判断了一些情况然后返回了 WindowManager.LayoutParams attrs = win != null ? win.getAttrs() : null; if (attrs != null) { final int type = attrs.type; if (type == WindowManager.LayoutParams.TYPE_KEYGUARD || type == WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG) { // the "app" is keyguard, so give it the key return 0; } final int typeCount = WINDOW_TYPES_WHERE_HOME_DOESNT_WORK.length; for (int i=0; i launch home action was detected. Take the appropriate action * given the situation with the keyguard. */ void launchHomeFromHotKey() { if (mKeyguardMediator.isShowingAndNotHidden()) { // don't launch home if keyguard showing //这个keyguard不知道是什么东东，反正它启动了就不响应Home键，系统已经处理了，跟Launcher没关系 } else if (!mHideLockScreen && mKeyguardMediator.isInputRestricted()) { // when in keyguard restricted mode, must first verify unlock // before launching home mKeyguardMediator.verifyUnlock(new OnKeyguardExitResult() { public void onKeyguardExitResult(boolean success) { if (success) { try { ActivityManagerNative.getDefault().stopAppSwitches();//关闭这个东东 } catch (RemoteException e) { } sendCloseSystemWindows(SYSTEM_DIALOG_REASON_HOME_KEY);//关闭这个东东 startDockOrHome();//启动Dock或者Home 很明显这三个函数都很重要 一个一个去看看 } } }); } else { // no keyguard stuff to worry about, just launch home! //这里跟上面是一样处理的 try { ActivityManagerNative.getDefault().stopAppSwitches(); } catch (RemoteException e) { } sendCloseSystemWindows(SYSTEM_DIALOG_REASON_HOME_KEY); startDockOrHome(); } }进入sendCloseSystemWindows,startDockOrHome两个函数看看 void sendCloseSystemWindows() { sendCloseSystemWindows(mContext, null); } void sendCloseSystemWindows(String reason) { sendCloseSystemWindows(mContext, reason); } static void sendCloseSystemWindows(Context context, String reason) { if (ActivityManagerNative.isSystemReady()) { try { ActivityManagerNative.getDefault().closeSystemDialogs(reason);//又是调用这个了 } catch (RemoteException e) { } } } void startDockOrHome() { Intent dock = createHomeDockIntent(); if (dock != null) { try { mContext.startActivity(dock);//启动HomeDock这个Dock好像是自定义的主界面，这里就不管了 return; } catch (ActivityNotFoundException e) { } } mContext.startActivity(mHomeIntent);//启动HomeIntent（其实就是发一个Intent消息到主界面） }我们再看看mHomeIntent是怎么定义的Intent mHomeIntent;mHomeIntent = new Intent(Intent.ACTION_MAIN, null);mHomeIntent.addCategory(Intent.CATEGORY_HOME);mHomeIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);Launcher中接受Intent的地方在Launcher2\Launcher2\src\com\android\launcher2\launcher.javaprotected void onNewIntent(Intent intent) {}函数中这里就不分析了，先试试能不能接受到再说。nnd搞了半天Launcher根本没接受Home键，按Home键时farmwork直接给Launcher调到最前面来了。
Simone
