Android获取内存大小

        ActivityManager activityManager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);    
 
        ActivityManager.MemoryInfo info = new ActivityManager.MemoryInfo();   
 
        activityManager.getMemoryInfo(info);    
 
        Log.i(tag,"系统剩余内存:"+(info.availMem >> 10)+"k");   
 
        Log.i(tag,"系统是否处于低内存运行："+info.lowMemory);
 
        Log.i(tag,"当系统剩余内存低于"+info.threshold+"时就看成低内存运行");

注意：HUAWEI PLK-UL00 Android 6.0 API23
在oom的时候(app内存达到450M)然而info.lowMemory=false
并且onTrimMemory和onLowMemory都没有回调