收集整理android 进程保活方法

1像素Activity

注册监听屏幕开启和屏幕关闭时的广播，当屏幕关闭时，开启1像素的 Activity, 当屏幕开启时，关闭1像素的 Activity.

查看进程等级

可以在studio 终端进行命令行, pid 进程id

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adb shell
su
cat proc/{pid}/oom_adj

OnePxActivity

public class OnePxActivity extends AppCompatActivity {

    public static void launch(Context context){
        Intent intent = new Intent(context,OnePxActivity.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(intent);
    }

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Log.i("qq","OnPxActivity onCreate.........");
        Window window = getWindow();
        window.setGravity(Gravity.START | Gravity.TOP);

        WindowManager.LayoutParams params = window.getAttributes();
        params.x = 0;
        params.y = 0;
        params.width = 1;
        params.height = 1;
        window.setAttributes(params);

        KeepAliveManager.getInstance().setKeepAliveManager(this);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.i("qq","OnPxActivity onDestroy.........");
    }
}

广播：监听开启/关闭的广播

public class KeepAliveReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {

        if(intent.getAction().equals(Intent.ACTION_SCREEN_ON)){
            //屏幕点亮
            Log.i("qq","收到屏幕开启广播");
            KeepAliveManager.getInstance().finishOnePxActivity(context);

        }else if(intent.getAction().equals(Intent.ACTION_SCREEN_OFF)){
            //屏幕熄灭, 启动activity
            Log.i("qq","收到屏幕关闭广播");
            KeepAliveManager.getInstance().startOnePxActivity(context);
        }
    }
}

辅助类：KeepAliveManager

public class KeepAliveManager {

    private KeepAliveManager(){}
    private static KeepAliveManager mInstance = new KeepAliveManager();

    private  WeakReference<OnePxActivity> mReference;

    public void setKeepAliveManager(OnePxActivity activity){
        this.mReference = new WeakReference<>(activity);
    }
    public static KeepAliveManager getInstance(){
        return mInstance;
    }

    public void startOnePxActivity(Context context){
        OnePxActivity.launch(context);
    }

    public void finishOnePxActivity(Context context){
        if(null != mReference && mReference.get() != null){
            mReference.get().finish();
        }
    }
    private KeepAliveReceiver mReceiver;
    public void registerReceiver(Context context){
        this.mReceiver = new KeepAliveReceiver();
        IntentFilter filter = new IntentFilter();
        filter.addAction(Intent.ACTION_SCREEN_OFF);
        filter.addAction(Intent.ACTION_SCREEN_ON);
        context.registerReceiver(mReceiver,filter);
    }

    public void unregisterReceiver(Context context){
        if(null != mReceiver){
            context.unregisterReceiver(mReceiver);
        }
    }
}

MainActivity 使用：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //第一种方式
        KeepAliveManager.getInstance().registerReceiver(this);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        KeepAliveManager.getInstance().unregisterReceiver(this);
    }
}

亲身实践了，发现确实oom_adj 变小，被杀死的概率比较低了，当屏幕变暗的时候。

前台服务

ForegroundService.java :

public class ForgroundService extends Service {

    private final int SERVICE_ID = 1;
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        if(Build.VERSION.SDK_INT < 18){
            //设置成前台服务，并且不显示通知栏消息
            startForeground(SERVICE_ID,new Notification());
        }else if(Build.VERSION.SDK_INT < 26){
            startForeground(SERVICE_ID,new Notification());
            startService(new Intent(this,InnerService.class));
        }else{//android 8.0

            NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
            if(manager != null){
                NotificationChannel channel = new NotificationChannel("channel","name",NotificationManager.IMPORTANCE_NONE);
                manager.createNotificationChannel(channel);
                NotificationCompat.Builder builder = new NotificationCompat.Builder(this,"channel");
				//设置成前台服务，Android9.0 会有通知栏消息，需要添加新的权限
                //<uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>
                startForeground(SERVICE_ID,builder.build());
            }
        }

        return super.onStartCommand(intent, flags, startId);
    }

    class InnerService extends Service{

        @Override
        public IBinder onBind(Intent intent) {

            return null;
        }

        @Override
        public int onStartCommand(Intent intent, int flags, int startId) {
            startForeground(SERVICE_ID,new Notification());
            stopForeground(true);
            stopSelf();
            return super.onStartCommand(intent, flags, startId);
        }
    }
}

双进程守护

后续补上…