Android中Home键的监听和拦截
16lz
2022-03-23
首先大家应该先了解一种情况，就是Android在应用中是无法拦截Home键的，今天我们带大家看一下Home键的三种情况。
1、在应用中按下Home键的逻辑处理
当我们在应用中按下Home键时界面会启动到桌面，我们在frameworks\base\policy\src\com\android\internal\policy\impl\PhoneWindowManager.Java类中可以看到其实现原理，其不外乎就是调用了以下代码。
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);- 1
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创建一个启动到桌面的Intent。
2、在应用中监听Home键
在Android应用中如果想监听Home键可以使用广播机制，这个在源码中也有体现。
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键会发送ACTION_CLOSE_SYSTEM_DIALOGS的广播 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键 Toast.makeText(arg0, "短按Home键", Toast.LENGTH_SHORT).show(); } else if (reason.equals(SYSTEM_DIALOG_REASON_RECENT_APPS)) { // RECENT_APPS键 Toast.makeText(arg0, "RECENT_APPS", Toast.LENGTH_SHORT).show(); } } } }- 1
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这样就可以监听Home的是否被按下。
3、在Frameworks层拦截Home键
在frameworks\base\policy\src\com\android\internal\policy\impl\PhoneWindowManager.java文件中我们首先看一下interceptKeyBeforeDispatching()方法。
public long interceptKeyBeforeDispatching(WindowState win, KeyEvent event, int policyFlags) { //...... if (keyCode == KeyEvent.KEYCODE_HOME) { //...... handleShortPressOnHome(); }}//进入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(); }- 1
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进入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); //启动Launcher界面 startDockOrHome(); } } }- 1
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以上方法可处理Home键的拦截操作，接下来我们进入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的相关设置 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); }- 1
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好啦，这里就对Home键进行简单的监听和拦截。
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