一、常见保活方案1、监听广播：监听全局的静态广播，比如时间更新的广播、开机广播、解锁屏、网络状态、解锁加锁亮屏暗屏（3.1版本），高版本需要应用开机后运行一次才能监听这些系统广播，目前此方案失效。可以更换思路，做APP启动后的保活（监听广播启动保活的前台服务）2、定时器、JobScheduler：假如应用被系统杀死，那么定时器则失效，此方案失效。JobService在5.0,5.1,6.0作用很大，7.0时候有一定影响（可以在电源管理中给APP授权）3、双进程（NDK方式Fork子进程）、双Service守护：高版本已失效，5.0起系统回收策略改成进程组。双Service方案也改成了应用被杀，任何后台Service无法正常状态运行4、提高Service优先级：只能一定程度上缓解Service被立马回收二、保活1、AIDL方式单进程、双进程方式保活Service2、降低oom_adj的值：常驻通知栏（可通过启动另外一个服务关闭Notification，不对oom_adj值有影响）、使用”1像素“的Activity覆盖在getWindow()的view上、循环播放无声音频（黑科技，7.0下杀不掉）3、监听锁屏广播：使Activity始终保持前台4、使用自定义锁屏界面：覆盖了系统锁屏界面。5、通过android:process属性来为Service创建一个进程6、跳转到系统白名单界面让用户自己添加app进入白名单三、复活1、JobScheduler：原理类似定时器，5.0,5.1,6.0作用很大，7.0时候有一定影响（可以在电源管理中给APP授权）2、推送互相唤醒复活：极光、友盟、以及各大厂商的推送3、同派系APP广播互相唤醒：比如今日头条系、阿里系方案实现效果统计1、双进程守护方案（基于onStartCommand() return START_STICKY）1、原生5.0、5.1：原生任务栏滑动清理app，Service会被杀掉，然后被拉起，接着一直存活2、金立F100(5.1)：一键清理直接杀掉整个app，包括双守护进程。不手动清理情况下，经测试能锁屏存活至少40分钟3、华为畅享5x（6.0）：一键清理直接杀掉整个app，包括双守护进程。不手动清理下，锁屏只存活10s。结论：双进程守护方案失效。4、美图m8s(7.1.1)：一键清理直接杀掉整个app，包括双守护进程。不清理情况下，锁屏会有被杀过程（9分钟左右被杀），之后重新复活，之后不断被干掉然后又重新复活。结论：双守护进程可在后台不断拉起Service。5、原生7.0：任务栏清除APP后，Service存活。使用此方案后Service照样存活。6、LG V30+(7.1.2)：不加双进程守护的时候，一键清理无法杀掉服务。加了此方案之后也不能杀掉服务，锁屏存活（测试观察大于50分钟）7、小米8(8.1)：一键清理直接干掉app并且包括双守护进程。不清理情况下，不加守护进程方案与加守护进程方案Service会一直存活，12分钟左右closed。结论：此方案没有起作用结论：除了华为此方案无效以及未更改底层的厂商不起作用外（START_STICKY字段就可以保持Service不被杀）。此方案可以与其他方案混合使用2、监听锁屏广播打开1像素Activity（基于onStartCommand() return START_STICKY）1、原生5.0、5.1：锁屏后3s服务被干掉然后重启（START_STICKY字段起作用）2、华为畅享5x（6.0）：锁屏只存活4s。结论：方案失效。3、美图m8s(7.1.1)：同原生5.04、原生7.0：同美图m8s。5、LG V30+(7.1.2)：锁屏后情况跟不加情况一致，服务一致保持运行，结论：此方案不起作用6、小米8(8.1)：关屏过2s之后app全部被干掉。结论：此方案没有起作用结论：此方案无效果3、故意在后台播放无声的音乐（基于onStartCommand() return START_STICKY）1、原生5.0、5.1：锁屏后3s服务被干掉然后重启（START_STICKY字段起作用）2、华为畅享5x（6.0）：一键清理后服务依然存活，需要单独清理才可杀掉服务，锁屏8分钟后依然存活。结论：此方案适用3、美图m8s(7.1.1)：同5.04、原生7.0：任务管理器中关闭APP后服务被干掉，大概过3s会重新复活（同仅START_STICKY字段模式）。结论：看不出此方案有没有其作用5、LG V30+(7.1.2)：使用此方案前后效果一致。结论：此方案不起作用6、小米8(8.1)：一键清理可以杀掉服务。锁屏后保活超过20分钟结论：成功对华为手机保活。小米8下也成功突破20分钟4、使用JobScheduler唤醒Service（基于onStartCommand() return START_STICKY）1、原生5.0、5.1：任务管理器中干掉APP，服务会在周期时间后重新启动。结论：此方案起作用2、华为畅享5x（6.0）：一键清理直接杀掉APP，过12s左右会自动重启服务，JobScheduler起作用3、美图m8s(7.1.1)：一键清理直接杀掉APP，无法自动重启4、原生7.0：同美图m8s(7.1.1)5、小米8(8.1)：同美图m8s(7.1.1)结论：只对5.0，5.1、6.0起作用5、混合使用的效果，并且在通知栏弹出通知1、原生5.0、5.1：任务管理器中干掉APP，服务会在周期时间后重新启动。锁屏超过11分钟存活2、华为畅享5x（6.0）：一键清理后服务依然存活，需要单独清理才可杀掉服务。结论：方案适用。3、美图m8s(7.1.1)：一键清理APP会被杀掉。正常情况下锁屏后服务依然存活。4、原生7.0：任务管理器中关闭APP后服务被干掉，过2s会重新复活5、小米8(8.1)：一键清理可以杀掉服务，锁屏下后台保活时间超过38分钟6、荣耀10（8.0）：一键清理杀掉服务，锁屏下后台保活时间超过23分钟结论：高版本情况下可以使用弹出通知栏、双进程、无声音乐提高后台服务的保活概率实现具体过程一、双进程实现方案使用AIDL绑定方式新建2个Service优先级（防止服务同时被系统杀死）不一样的守护进程互相拉起对方，并在每一个守护进程的ServiceConnection的绑定回调里判断保活Service是否需要重新拉起和对守护线程进行重新绑定。1、新建一个AIDL文件KeepAliveConnectioninterface KeepAliveConnection {}2、新建一个服务类StepService，onBind()方法返回new KeepAliveConnection.Stub()对象，并在ServiceConnection的绑定回调中对守护进程服务类GuardService的启动和绑定。/** * 主进程 双进程通讯 * * @author LiGuangMin * @time Created by 2018/8/17 11:26 /public class StepService extends Service { private final static String TAG = StepService.class.getSimpleName(); private ServiceConnection mServiceConnection = new ServiceConnection() { @Override public void onServiceConnected(ComponentName componentName, IBinder iBinder) { Logger.d(TAG, “StepService:建立链接”); boolean isServiceRunning = ServiceAliveUtils.isServiceAlice(); if (!isServiceRunning) { Intent i = new Intent(StepService.this, DownloadService.class); startService(i); } } @Override public void onServiceDisconnected(ComponentName componentName) { // 断开链接 startService(new Intent(StepService.this, GuardService.class)); // 重新绑定 bindService(new Intent(StepService.this, GuardService.class), mServiceConnection, Context.BIND_IMPORTANT); } }; @Nullable @Override public IBinder onBind(Intent intent) { return new KeepAliveConnection.Stub() { }; } @Override public int onStartCommand(Intent intent, int flags, int startId) { startForeground(1, new Notification()); // 绑定建立链接 bindService(new Intent(this, GuardService.class), mServiceConnection, Context.BIND_IMPORTANT); return START_STICKY; }}3、对守护进程GuardService进行和2一样的处理/* * 守护进程 双进程通讯 * * @author LiGuangMin * @time Created by 2018/8/17 11:27 /public class GuardService extends Service { private final static String TAG = GuardService.class.getSimpleName(); private ServiceConnection mServiceConnection = new ServiceConnection() { @Override public void onServiceConnected(ComponentName componentName, IBinder iBinder) { Logger.d(TAG, “GuardService:建立链接”); boolean isServiceRunning = ServiceAliveUtils.isServiceAlice(); if (!isServiceRunning) { Intent i = new Intent(GuardService.this, DownloadService.class); startService(i); } } @Override public void onServiceDisconnected(ComponentName componentName) { // 断开链接 startService(new Intent(GuardService.this, StepService.class)); // 重新绑定 bindService(new Intent(GuardService.this, StepService.class), mServiceConnection, Context.BIND_IMPORTANT); } }; @Nullable @Override public IBinder onBind(Intent intent) { return new KeepAliveConnection.Stub() { }; } @Override public int onStartCommand(Intent intent, int flags, int startId) { startForeground(1, new Notification()); // 绑定建立链接 bindService(new Intent(this, StepService.class), mServiceConnection, Context.BIND_IMPORTANT); return START_STICKY; }}4、在Activity中在启动需要保活的DownloadService服务后然后启动保活的双进程public class MainActivity extends AppCompatActivity { private TextView mShowTimeTv; private DownloadService.DownloadBinder mDownloadBinder; private ServiceConnection mServiceConnection = new ServiceConnection() { @Override public void onServiceConnected(ComponentName name, IBinder service) { mDownloadBinder = (DownloadService.DownloadBinder) service; mDownloadBinder.setOnTimeChangeListener(new DownloadService.OnTimeChangeListener() { @Override public void showTime(final String time) { runOnUiThread(new Runnable() { @Override public void run() { mShowTimeTv.setText(time); } }); } }); } @Override public void onServiceDisconnected(ComponentName name) { } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Intent intent = new Intent(this, DownloadService.class); startService(intent); bindService(intent, mServiceConnection, Context.BIND_AUTO_CREATE); //双守护线程，优先级不一样 startAllServices(); } @Override public void onContentChanged() { super.onContentChanged(); mShowTimeTv = findViewById(R.id.tv_show_time); } @Override protected void onDestroy() { super.onDestroy(); unbindService(mServiceConnection); } /* * 开启所有守护Service / private void startAllServices() { startService(new Intent(this, StepService.class)); startService(new Intent(this, GuardService.class)); }}二、监听到锁屏广播后使用“1”像素Activity提升优先级1、该Activity的View只要设置为1像素然后设置在Window对象上即可。在Activity的onDestroy周期中进行保活服务的存活判断从而唤醒服务。“1像素"Activity如下public class SinglePixelActivity extends AppCompatActivity { private static final String TAG = SinglePixelActivity.class.getSimpleName(); @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); Window mWindow = getWindow(); mWindow.setGravity(Gravity.LEFT | Gravity.TOP); WindowManager.LayoutParams attrParams = mWindow.getAttributes(); attrParams.x = 0; attrParams.y = 0; attrParams.height = 1; attrParams.width = 1; mWindow.setAttributes(attrParams); ScreenManager.getInstance(this).setSingleActivity(this); } @Override protected void onDestroy() { if (!SystemUtils.isAppAlive(this, Constant.PACKAGE_NAME)) { Intent intentAlive = new Intent(this, DownloadService.class); startService(intentAlive); } super.onDestroy(); }}2、对广播进行监听，封装为一个ScreenReceiverUtil类，进行锁屏解锁的广播动态注册监听public class ScreenReceiverUtil { private Context mContext; private SreenBroadcastReceiver mScreenReceiver; private SreenStateListener mStateReceiverListener; public ScreenReceiverUtil(Context mContext) { this.mContext = mContext; } public void setScreenReceiverListener(SreenStateListener mStateReceiverListener) { this.mStateReceiverListener = mStateReceiverListener; // 动态启动广播接收器 this.mScreenReceiver = new SreenBroadcastReceiver(); IntentFilter filter = new IntentFilter(); filter.addAction(Intent.ACTION_SCREEN_ON); filter.addAction(Intent.ACTION_SCREEN_OFF); filter.addAction(Intent.ACTION_USER_PRESENT); mContext.registerReceiver(mScreenReceiver, filter); } public void stopScreenReceiverListener() { mContext.unregisterReceiver(mScreenReceiver); } /* * 监听sreen状态对外回调接口 / public interface SreenStateListener { void onSreenOn(); void onSreenOff(); void onUserPresent(); } public class SreenBroadcastReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (mStateReceiverListener == null) { return; } if (Intent.ACTION_SCREEN_ON.equals(action)) { // 开屏 mStateReceiverListener.onSreenOn(); } else if (Intent.ACTION_SCREEN_OFF.equals(action)) { // 锁屏 mStateReceiverListener.onSreenOff(); } else if (Intent.ACTION_USER_PRESENT.equals(action)) { // 解锁 mStateReceiverListener.onUserPresent(); } } }}3、对1像素Activity进行防止内存泄露的处理，新建一个ScreenManager类public class ScreenManager { private static final String TAG = ScreenManager.class.getSimpleName(); private static ScreenManager sInstance; private Context mContext; private WeakReference<Activity> mActivity; private ScreenManager(Context mContext) { this.mContext = mContext; } public static ScreenManager getInstance(Context context) { if (sInstance == null) { sInstance = new ScreenManager(context); } return sInstance; } /* 获得SinglePixelActivity的引用 * @param activity / public void setSingleActivity(Activity activity) { mActivity = new WeakReference<>(activity); } /* * 启动SinglePixelActivity / public void startActivity() { Intent intent = new Intent(mContext, SinglePixelActivity.class); intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); mContext.startActivity(intent); } /* * 结束SinglePixelActivity / public void finishActivity() { if (mActivity != null) { Activity activity = mActivity.get(); if (activity != null) { activity.finish(); } } }}4、对1像素的Style进行特殊处理，在style文件中新建一个SingleActivityStyle<style name=“SingleActivityStyle” parent=“android:Theme.Holo.Light.NoActionBar”> <item name=“android:windowBackground”>@android:color/transparent</item> <item name=“android:windowFrame”>@null</item> <item name=“android:windowNoTitle”>true</item> <item name=“android:windowIsFloating”>true</item> <item name=“android:windowContentOverlay”>@null</item> <item name=“android:backgroundDimEnabled”>false</item> <item name=“android:windowAnimationStyle”>@null</item> <item name=“android:windowDisablePreview”>true</item> <item name=“android:windowNoDisplay”>false</item>5、让SinglePixelActivity使用singleInstance启动模式，在manifest文件中 <activity android:name=".activity.SinglePixelActivity” android:configChanges=“keyboardHidden|orientation|screenSize|navigation|keyboard” android:excludeFromRecents=“true” android:finishOnTaskLaunch=“false” android:launchMode=“singleInstance” android:theme="@style/SingleActivityStyle" />6、在保活服务类DownloadService中对监听的广播进行注册和对SinglePixelActivity进行控制。public class DownloadService extends Service { public static final int NOTICE_ID = 100; private static final String TAG = DownloadService.class.getSimpleName(); private DownloadBinder mDownloadBinder; private NotificationCompat.Builder mBuilderProgress; private NotificationManager mNotificationManager; private ScreenReceiverUtil mScreenListener; private ScreenManager mScreenManager; private Timer mRunTimer; private int mTimeSec; private int mTimeMin; private int mTimeHour; private ScreenReceiverUtil.SreenStateListener mScreenListenerer = new ScreenReceiverUtil.SreenStateListener() { @Override public void onSreenOn() { mScreenManager.finishActivity(); Logger.d(TAG, “关闭了1像素Activity”); } @Override public void onSreenOff() { mScreenManager.startActivity(); Logger.d(TAG, “打开了1像素Activity”); } @Override public void onUserPresent() { } }; private OnTimeChangeListener mOnTimeChangeListener; @Override public void onCreate() { super.onCreate();// 注册锁屏广播监听器 mScreenListener = new ScreenReceiverUtil(this); mScreenManager = ScreenManager.getInstance(this); mScreenListener.setScreenReceiverListener(mScreenListenerer); mDownloadBinder = new DownloadBinder(); mNotificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE); } @Override public int onStartCommand(Intent intent, int flags, int startId) { Logger.d(TAG, “onStartCommand”); startRunTimer(); return START_STICKY; } @Nullable @Override public IBinder onBind(Intent intent) { return mDownloadBinder; } @Override public boolean onUnbind(Intent intent) { Logger.d(TAG, “onUnbind”); return super.onUnbind(intent); } @Override public void onDestroy() { super.onDestroy(); NotificationManager mManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE); if (mManager == null) { return; } mManager.cancel(NOTICE_ID); stopRunTimer();// mScreenListener.stopScreenReceiverListener(); } private void startRunTimer() { TimerTask mTask = new TimerTask() { @Override public void run() { mTimeSec++; if (mTimeSec == 60) { mTimeSec = 0; mTimeMin++; } if (mTimeMin == 60) { mTimeMin = 0; mTimeHour++; } if (mTimeHour == 24) { mTimeSec = 0; mTimeMin = 0; mTimeHour = 0; } String time = “时间为：” + mTimeHour + " : " + mTimeMin + " : " + mTimeSec; if (mOnTimeChangeListener != null) { mOnTimeChangeListener.showTime(time); } Logger.d(TAG, time); } }; mRunTimer = new Timer(); // 每隔1s更新一下时间 mRunTimer.schedule(mTask, 1000, 1000); } private void stopRunTimer() { if (mRunTimer != null) { mRunTimer.cancel(); mRunTimer = null; } mTimeSec = 0; mTimeMin = 0; mTimeHour = 0; Logger.d(TAG, “时间为：” + mTimeHour + " : " + mTimeMin + " : " + mTimeSec); } public interface OnTimeChangeListener { void showTime(String time); } public class DownloadBinder extends Binder { public void setOnTimeChangeListener(OnTimeChangeListener onTimeChangeListener) { mOnTimeChangeListener = onTimeChangeListener; } }}3、在后台播放音乐1、准备一段无声的音频，新建一个播放音乐的Service类，将播放模式改为无限循环播放。在其onDestroy方法中对自己重新启动。public class PlayerMusicService extends Service { private final static String TAG = PlayerMusicService.class.getSimpleName(); private MediaPlayer mMediaPlayer; @Nullable @Override public IBinder onBind(Intent intent) { return null; } @Override public void onCreate() { super.onCreate(); Logger.d(TAG, TAG + “—->onCreate,启动服务”); mMediaPlayer = MediaPlayer.create(getApplicationContext(), R.raw.silent); mMediaPlayer.setLooping(true); } @Override public int onStartCommand(Intent intent, int flags, int startId) { new Thread(new Runnable() { @Override public void run() { startPlayMusic(); } }).start(); return START_STICKY; } private void startPlayMusic() { if (mMediaPlayer != null) { Logger.d(TAG, “启动后台播放音乐”); mMediaPlayer.start(); } } private void stopPlayMusic() { if (mMediaPlayer != null) { Logger.d(TAG, “关闭后台播放音乐”); mMediaPlayer.stop(); } } @Override public void onDestroy() { super.onDestroy(); stopPlayMusic(); Logger.d(TAG, TAG + “—->onCreate,停止服务”); // 重启自己 Intent intent = new Intent(getApplicationContext(), PlayerMusicService.class); startService(intent); }}2、 在保活的DownloadServie服务类的onCreate方法中对PlayerMusicService进行启动 Intent intent = new Intent(this, PlayerMusicService.class); startService(intent);3、在Manifest文件中进行注册 <service android:name=".service.PlayerMusicService" android:enabled=“true” android:exported=“true” android:process=":music_service" />4、使用JobScheduler唤醒Service1、新建一个继承自JobService的ScheduleService类，在其onStartJob回调中对DownloadService进行存活的判断来重启。public class ScheduleService extends JobService { private static final String TAG = ScheduleService.class.getSimpleName(); @Override public boolean onStartJob(JobParameters params) { boolean isServiceRunning = ServiceAliveUtils.isServiceAlice(); if (!isServiceRunning) { Intent i = new Intent(this, DownloadService.class); startService(i); Logger.d(TAG, “ScheduleService启动了DownloadService”); } jobFinished(params, false); return false; } @Override public boolean onStopJob(JobParameters params) { return false; }}2、 在DownloadService服务类中进行JobScheduler的注册和使用 /* * 使用JobScheduler进行保活 */ private void useJobServiceForKeepAlive() { JobScheduler jobScheduler = (JobScheduler) getSystemService(Context.JOB_SCHEDULER_SERVICE); if (jobScheduler == null) { return; } jobScheduler.cancelAll(); JobInfo.Builder builder = new JobInfo.Builder(1024, new ComponentName(getPackageName(), ScheduleService.class.getName())); //周期设置为了2s builder.setPeriodic(1000 * 2); builder.setPersisted(true); builder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_ANY); int schedule = jobScheduler.schedule(builder.build()); if (schedule <= 0) { Logger.w(TAG, “schedule error！”); } }3、在manifest文件中进行权限设置 <service android:name=".service.ScheduleService" android:enabled=“true” android:exported=“true” android:permission=“android.permission.BIND_JOB_SERVICE” />关于推送类拉活根据华为官方文档集成HUAWEI Push1、华为畅玩5X(6.0)：APP全部进程被杀死时可以被拉起。2、华为nove 3e（8.0)：APP全部进程被杀死时无法被拉起，能收到推送。3、华为荣耀10（8.1）：同2结论：理论情况下，华为推送应该可以拉起华为机器才对，感觉是我没花钱的原因补充：ServiceAliveUtils 类如下public class ServiceAliveUtils { public static boolean isServiceAlice() { boolean isServiceRunning = false; ActivityManager manager = (ActivityManager) MyApplication.getMyApplication().getSystemService(Context.ACTIVITY_SERVICE); if (manager == null) { return true; } for (ActivityManager.RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) { if (“demo.lgm.com.keepalivedemo.service.DownloadService”.equals(service.service.getClassName())) { isServiceRunning = true; } } return isServiceRunning; }}作者：minminaya链接：https://www.jianshu.com/p/b53…阅读更多做后台是选择Java 、Go ，还是 PHP?NDK项目实战—高仿360手机助手之卸载监听AndroidUtils：Android开发不得不收藏的Utils（Android）面试题级答案（精选版）Google开发者大会：你不得不知的Tensorflow小技巧相信自己，没有做不到的，只有想不到的在这里获得的不仅仅是技术！
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