在Davilk中，给一个程序分配的内存依据机型厂商的不同，而不同。如今的大部分的是32M了。而在VM内部会把这些内存分成java使用的内存和 Native使用的内存，它们之间是不能共享的。就是说当你的Native内存用完了。如今Java又有空暇的内存。这时Native会又一次像VM申请，而不是直接使用java的。

比如上边的样例

explicit 3411K/6663K

external 24870K/26260K

假设这时须要创建一个2M的

Bitmap，

Native现有内存26260-24870=1390K<2048k,因此他就会向Vm申请内存，尽管java空暇的内存是

6663-3411=3252>2048,但这部分内存Native是不能使用。

可是你如今去申请2M的Native内存，VM会告诉你无法分配的，由于如今已使用的内存已经接近峰值了32M(26260+6663=32923 )，所以如今就会成force close 报OOM。

所以如今我们要检查我们的native内存的使用情况来避免OOM。

ps: http://*.com/questions/2298208/how-to-discover-memory-usage-of-my-application-in-android#2299813

三、通过Android系统提供的Runtime类，运行adb 命令(top,procrank,ps...等命令)查询

内存耗用：VSS/RSS/PSS/USS

Terms

? VSS - Virtual Set Size 虚拟耗用内存（包括共享库占用的内存）

?

RSS - Resident Set Size 实际使用物理内存（包括共享库占用的内存）

? PSS - Proportional Set Size 实际使用的物理内存（比例分配共享库占用的内存）

? USS - Unique Set Size 进程独自占用的物理内存（不包括共享库占用的内存）

一般来说内存占用大小有例如以下规律：VSS >= RSS >= PSS >= USS

查看每一个进程及其内存状况

	private void getRunningAppProcessInfo() {

		mActivityManager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);

		// 获得系统里正在执行的全部进程

		List<RunningAppProcessInfo> runningAppProcessesList = mActivityManager

				.getRunningAppProcesses();

		for (RunningAppProcessInfo runningAppProcessInfo : runningAppProcessesList) {

			// 进程ID号

			int pid = runningAppProcessInfo.pid;

			// 用户ID

			int uid = runningAppProcessInfo.uid;

			// 进程名

			String processName = runningAppProcessInfo.processName;

			// 占用的内存

			int[] pids = new int[] { pid };

			Debug.MemoryInfo[] memoryInfo = mActivityManager

					.getProcessMemoryInfo(pids);

			int memorySize = memoryInfo[0].dalvikPrivateDirty;

			st = st + "processName=" + processName + ",pid=" + pid + ",uid="

					+ uid + ",memorySize=" + memorySize + "kb" + "\n";

			System.out.println("processName=" + processName + ",pid=" + pid

					+ ",uid=" + uid + ",memorySize=" + memorySize + "kb");

		}

	}

查看总内存：

	public long getmem_TOLAL() {

		long mTotal;

		// /proc/meminfo读出的内核信息进行解释

		String path = "/proc/meminfo";

		String content = null;

		BufferedReader br = null;

		try {

			br = new BufferedReader(new FileReader(path), 8);

			String line;

			if ((line = br.readLine()) != null) {

				content = line;

			}

		} catch (FileNotFoundException e) {

			e.printStackTrace();

		} catch (IOException e) {

			e.printStackTrace();

		} finally {

			if (br != null) {

				try {

					br.close();

				} catch (IOException e) {

					e.printStackTrace();

				}

			}

		}

		// beginIndex

		int begin = content.indexOf(':');

		// endIndex

		int end = content.indexOf('k');

		// 截取字符串信息

		content = content.substring(begin + 1, end).trim();

		mTotal = Integer.parseInt(content);

		return mTotal;

	}

查看内存信息（该api较新）：

	public long getmem_UNUSED(Context mContext) {

		long MEM_UNUSED;

		// 得到ActivityManager

		ActivityManager am = (ActivityManager) mContext

				.getSystemService(Context.ACTIVITY_SERVICE);

		// 创建ActivityManager.MemoryInfo对象

		ActivityManager.MemoryInfo mi = new ActivityManager.MemoryInfo();

		am.getMemoryInfo(mi);

		textView3.setText("totalMen:" + mi.totalMem / 1024 + "\n"

				+ "threshold:" + mi.threshold / 1024 + "\n" + "availMem:"

				+ mi.availMem / 1024 + "\n");

		// 取得剩余的内存空间

		MEM_UNUSED = mi.availMem / 1024;

		return MEM_UNUSED;

	}

查看app内存：

	ActivityManager manager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);

	int i=manager.getMemoryClass();

	textView.setText("\n"+"app:"+i);

实例1

int cnt=0;

final static int kBufferMinSize=1000;

final static int kBufferMaxSize=2000;

StringBuffer strBuffer=new StringBuffer(kBufferMinSize);

StringBuffer strBuffer2=new StringBuffer(kBufferMinSize);

StringBuffer strBuffer3=new StringBuffer(kBufferMinSize);

StringBuffer strBufferNativePss=new StringBuffer(kBufferMinSize);

StringBuffer strBufferDalvikPss=new StringBuffer(kBufferMinSize);

StringBuffer strBufferOtherPss=new StringBuffer(kBufferMinSize);

Debug.MemoryInfo memoryInfo=new Debug.MemoryInfo();

final static String tag="robin";

void printMemory()

{

long totalMemory=Runtime.getRuntime().totalMemory();

long freeMemory=Runtime.getRuntime().freeMemory();

long usedMemory=(totalMemory-freeMemory)>>10;

totalMemory=totalMemory>>10;

freeMemory=freeMemory>>10;

if(strBuffer.length()>kBufferMaxSize)

{

strBuffer.delete(0,strBuffer.length());

strBuffer2.delete(0,strBuffer2.length());

strBuffer3.delete(0,strBuffer3.length());

strBufferNativePss.delete(0,strBufferNativePss.length());

strBufferDalvikPss.delete(0,strBufferDalvikPss.length());

}

strBuffer.append(usedMemory+",");

strBuffer2.append(totalMemory+",");

strBuffer3.append((Debug.getNativeHeapSize()>>10)+",");

Debug.getMemoryInfo(memoryInfo);

strBufferNativePss.append((memoryInfo.nativePss)+",");

strBufferDalvikPss.append((memoryInfo.dalvikPss)+",");

if(cnt++==0)

{

Log.i(tag,"usedMemory:"+strBuffer.toString());

Log.i(tag,"totalMemory:"+strBuffer2.toString());

Log.i(tag,"NativeHeapSize:"+strBuffer3.toString());

Log.i(tag,"Native PSS:"+strBufferNativePss.toString());

Log.i(tag,"Dalvik PSS:"+strBufferDalvikPss.toString());

}

}