前台服务可提高进程等级，提高App进程存活性
1. 服务
import android.app.Notification;
import android.app.NotificationManager;
import android.app.Service;
import android.content.Intent;
import android.os.Build;
import android.os.Handler;
import android.os.IBinder;
import android.support.annotation.Nullable;
import com.xxxx.xxxx.R;
import com.orhanobut.logger.Logger;
/**
* 描述:
* <p>
*
* @author allens
* @date 2018/1/23
*/
public class KeepLiveService extends Service {
public static final int NOTIFICATION_ID = 0x11;
public KeepLiveService() {
}
@Override
public IBinder onBind(Intent intent) {
throw new UnsupportedOperationException("Not yet implemented");
}
@Override
public void onCreate() {
super.onCreate();
Logger.e("KeepLiveService onCreate");
//API 18以下，直接发送Notification并将其置为前台
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR2) {
startForeground(NOTIFICATION_ID, new Notification());
} else {
//API 18以上，发送Notification并将其置为前台后，启动InnerService
Notification.Builder builder = new Notification.Builder(this);
builder.setSmallIcon(R.mipmap.water_icn)
//设置通知标题
.setContentTitle("xxx系统");
startForeground(NOTIFICATION_ID, builder.build());
startService(new Intent(this, InnerService.class));
}
}
public static class InnerService extends Service {
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onCreate() {
super.onCreate();
Logger.e("InnerService onCreate");
//发送与KeepLiveService中ID相同的Notification，然后将其取消并取消自己的前台显示
Notification.Builder builder = new Notification.Builder(this);
builder.setSmallIcon(R.mipmap.ic_launcher);
startForeground(NOTIFICATION_ID, builder.build());
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
stopForeground(true);
NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
manager.cancel(NOTIFICATION_ID);
stopSelf();
}
}, 100);
}
}
}
2.注册服务
<service android:name="com.xxx.xxxx.service.KeepLiveService" />
<service android:name="com$xxx$xxxx$service$KeepLiveService$InnerService" />
3.查看adj级别
-
8adb shell
-
ps|grep <package_name> 查看基本信息
1|root@generic_x86:/ # ps|grep com.cpsc.livedemo
u0_a63 6834 1348 1285208 43884 SyS_epoll_ b73712b5 S com.xxxx.livedemo
u0_a63 6884 1348 1271160 28944 SyS_epoll_ b73712b5 S com.xxxx.livedemo:daemon_service
| 值 | 解释 |
|---|---|
| u0_a63 | USER 进程当前用户 |
| 6834 | 进程ID |
| 1348 | 进程的父进程ID |
| 1285208 | 进程的虚拟内存大小 |
| 43884 | 实际驻留”在内存中”的内存大小 |
| com.cpsc.livedemo | 进程名 |
- cat /proc/<进程id>/oom_adj
root@generic_x86:/ # cat /proc/6884/oom_adj
1
root@generic_x86:/ # cat /proc/6884/oom_adj
1
root@generic_x86:/ #
| adj级别 | 值 | 说明 |
|---|---|---|
| UNKNOWN_ADJ | 16 | 预留的最低级别，一般对于缓存的进程才有可能设置成这个级别 |
| CACHED_APP_MAX_ADJ | 15 | 缓存进程，空进程，在内存不足的情况下就会优先被kill |
| CACHED_APP_MIN_ADJ | 9 | 缓存进程，也就是空进程 |
| SERVICE_B_ADJ | 8 | 不活跃的进程 |
| PREVIOUS_APP_ADJ | 7 | 切换进程 |
| HOME_APP_ADJ | 6 | 与Home交互的进程 |
| SERVICE_ADJ | 5 | 有Service的进程 |
| HEAVY_WEIGHT_APP_ADJ | 4 | 高权重进程 |
| BACKUP_APP_ADJ | 3 | 正在备份的进程 |
| PERCEPTIBLE_APP_ADJ | 2 | 可感知的进程，比如那种播放音乐 |
| VISIBLE_APP_ADJ | 1 | 可见进程 |
| FOREGROUND_APP_ADJ | 0 | 前台进程 |
| PERSISTENT_SERVICE_ADJ | -11 | 重要进程 |
| PERSISTENT_PROC_ADJ | -12 | 核心进程 |
| SYSTEM_ADJ | -16 | 系统进程 |
| NATIVE_ADJ | -17 | 系统起的Native进程 |
参考：
https://blog.csdn.net/andrexpert/article/details/75045678
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