首先大家應該先了解一種情況，就是Android在應用中是無法攔截Home鍵的，今天我們帶大家看一下Home鍵的三種情況。
1、在應用中按下Home鍵的邏輯處理
當我們在應用中按下Home鍵時界面會啟動到桌面，我們在frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.Java類中可以看到其實現原理，其不外乎就是調用了以下代碼。
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); startActivity(mHomeIntent);
創建一個啟動到桌面的Intent。
2、在應用中監聽Home鍵
在Android應用中如果想監聽Home鍵可以使用廣播機制，這個在源碼中也有體現。
static public final String SYSTEM_DIALOG_REASON_KEY = "reason"; static public final String SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS = "globalactions"; static public final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps"; static public final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey"; static public final String SYSTEM_DIALOG_REASON_ASSIST = "assist"; @Override public void onReceive(Context arg0, Intent arg1) { String action = arg1.getAction(); //按下Home鍵會發送ACTION_CLOSE_SYSTEM_DIALOGS的廣播 if (action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) { String reason = arg1.getStringExtra(SYSTEM_DIALOG_REASON_KEY); if (reason != null) { if (reason.equals(SYSTEM_DIALOG_REASON_HOME_KEY)) { // 短按home鍵 Toast.makeText(arg0, "短按Home鍵", Toast.LENGTH_SHORT).show(); } else if (reason.equals(SYSTEM_DIALOG_REASON_RECENT_APPS)) { // RECENT_APPS鍵 Toast.makeText(arg0, "RECENT_APPS", Toast.LENGTH_SHORT).show(); } } } }這樣就可以監聽Home的是否被按下。
3、在Frameworks層攔截Home鍵
在frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java文件中我們首先看一下interceptKeyBeforeDispatching()方法。
public long interceptKeyBeforeDispatching(WindowState win, KeyEvent event, int policyFlags) { //...... if (keyCode == KeyEvent.KEYCODE_HOME) { //...... handleShortPressOnHome(); }}//進入handleShortPressOnHomeprivate void handleShortPressOnHome() { // If there's a dream running then use home to escape the dream // but don't actually go home. if (mDreamManagerInternal != null && mDreamManagerInternal.isDreaming()) { mDreamManagerInternal.stopDream(false /*immediate*/); return; } // Go home! launchHomeFromHotKey(); }進入launchHomeFromHotKey方法。
static public final String SYSTEM_DIALOG_REASON_KEY = "reason"; static public final String SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS = "globalactions"; static public final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps"; static public final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey"; static public final String SYSTEM_DIALOG_REASON_ASSIST = "assist";void launchHomeFromHotKey() { if (isKeyguardShowingAndNotOccluded()) { // don't launch home if keyguard showing } else if (!mHideLockScreen && mKeyguardDelegate.isInputRestricted()) { // when in keyguard restricted mode, must first verify unlock // before launching home mKeyguardDelegate.verifyUnlock(new OnKeyguardExitResult() { @Override public void onKeyguardExitResult(boolean success) { if (success) { try { ActivityManagerNative.getDefault().stopAppSwitches(); } catch (RemoteException e) { } sendCloseSystemWindows(SYSTEM_DIALOG_REASON_HOME_KEY); startDockOrHome(); } } }); } else { // no keyguard stuff to worry about, just launch home! try { ActivityManagerNative.getDefault().stopAppSwitches(); } catch (RemoteException e) { } if (mRecentsVisible) { // Hide Recents and notify it to launch Home awakenDreams(); sendCloseSystemWindows(SYSTEM_DIALOG_REASON_HOME_KEY); hideRecentApps(false, true); } else { // Otherwise, just launch Home sendCloseSystemWindows(SYSTEM_DIALOG_REASON_HOME_KEY); //啟動Launcher界面 startDockOrHome(); } } }以上方法可處理Home鍵的攔截操作，接下來我們進入startDockOrHome方法。
void startDockOrHome() { if (OptConfig.LC_RAM_SUPPORT) { try { ActivityManagerNative.getDefault().startHomePre(); } catch (RemoteException re) { } } awakenDreams(); Intent dock = createHomeDockIntent(); if (dock != null) { try { startActivityAsUser(dock, UserHandle.CURRENT); return; } catch (ActivityNotFoundException e) { } } //intent的相關設置 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); startActivityAsUser(mHomeIntent, UserHandle.CURRENT); }好啦，這里就對Home鍵進行簡單的監聽和攔截。
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持VEVB武林網。
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