Android 擷取進程記憶體使用量情況方法

ActivityManager activityManager = (ActivityManager) context.getSystemService(ACTIVITY_SERVICE);MemoryInfo memoryInfo = new ActivityManager.MemoryInfo();activityManager.getMemoryInfo(memoryInfo);Log.i(TAG, " memoryInfo.availMem " + memoryInfo.availMem + "n" );Log.i(TAG, " memoryInfo.lowMemory " + memoryInfo.lowMemory + "n" );Log.i(TAG, " memoryInfo.threshold " + memoryInfo.threshold + "n" );List<RunningAppProcessInfo> runningAppProcesses = activityManager.getRunningAppProcesses();Map<Integer, String> pidMap = new TreeMap<Integer, String>();for (RunningAppProcessInfo runningAppProcessInfo : runningAppProcesses){    pidMap.put(runningAppProcessInfo.pid, runningAppProcessInfo.processName);}Collection<Integer> keys = pidMap.keySet();for(int key : keys){    int pids[] = new int[1];    pids[0] = key;    android.os.Debug.MemoryInfo[] memoryInfoArray = activityManager.getProcessMemoryInfo(pids);    for(android.os.Debug.MemoryInfo pidMemoryInfo: memoryInfoArray)    {        Log.i(TAG, String.format("** MEMINFO in pid %d [%s] **n",pids[0],pidMap.get(pids[0])));        Log.i(TAG, " pidMemoryInfo.getTotalPrivateDirty(): " + pidMemoryInfo.getTotalPrivateDirty() + "n");        Log.i(TAG, " pidMemoryInfo.getTotalPss(): " + pidMemoryInfo.getTotalPss() + "n");        Log.i(TAG, " pidMemoryInfo.getTotalSharedDirty(): " + pidMemoryInfo.getTotalSharedDirty() + "n");    }}

在看到上述代碼之前，自己按照API說明也寫了類似代碼如下，包含了更多的輸出參數。如果要檢查其他進程的記憶體使用量情況，可略去迴圈中的條件判斷。按stackoverflow.com中文章的說法 Pss的值是最能表明進程使用記憶體狀況

public long getmem_SELF() {        ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);        List<RunningAppProcessInfo> procInfo = am.getRunningAppProcesses();        for (RunningAppProcessInfo runningAppProcessInfo : procInfo) {          System.out.println(runningAppProcessInfo.processName+ String.format(",pid = %d", runningAppProcessInfo.pid));          if( runningAppProcessInfo.processName.indexOf(this.getPackageName()) != -1 )        {        int pids[] = {runningAppProcessInfo.pid};        Debug.MemoryInfo self_mi[] = am.getProcessMemoryInfo(pids);        StringBuffer  strbuf = new StringBuffer();        strbuf.append(" proccess Name:").append(runningAppProcessInfo.processName)        .append("n pid:").append(runningAppProcessInfo.pid)        .append("n dalvikPrivateDirty:").append(self_mi[0].dalvikPrivateDirty)    .append("n dalvikPss:").append(self_mi[0].dalvikPss)    .append("n dalvikSharedDirty:").append(self_mi[0].dalvikSharedDirty)    .append("n nativePrivateDirty:").append(self_mi[0].nativePrivateDirty)    .append("n nativePss:").append(self_mi[0].nativePss)    .append("n nativeSharedDirty:").append(self_mi[0].nativeSharedDirty)    .append("n otherPrivateDirty:").append(self_mi[0].otherPrivateDirty)    .append("n otherPss:").append(self_mi[0].otherPss)    .append("n otherSharedDirty:").append(self_mi[0].otherSharedDirty)    .append("n TotalPrivateDirty:").append(self_mi[0].getTotalPrivateDirty())    .append("n TotalPss:").append(self_mi[0].getTotalPss())    .append("n TotalSharedDirty:").append(self_mi[0].getTotalSharedDirty());        Log.v("TEST",strbuf.toString());        }}<div class="dp-highlighter bg_java"><div class="bar"><div class="tools"><b>[java]</b> <a href="#" class="ViewSource" title="view plain" onclick="dp.sh.Toolbar.Command('ViewSource',this);return false;">view plain</a><a href="#" class="CopyToClipboard" title="copy onclick="dp.sh.Toolbar.Command('CopyToClipboard',this);return false;">copy</a><a href="#" class="PrintSource" title="print" onclick="dp.sh.Toolbar.Command('PrintSource',this);return false;">print</a><a href="#" class="About" title="?" onclick="dp.sh.Toolbar.Command('About',this);return false;">?</a><div style="position: absolute; left: 0px; top: 0px; width: 0px; height: 0px; z-index: 99; "><embed id="ZeroClipboardMovie_3" src="http://static.blog.csdn.net/scripts/ZeroClipboard/ZeroClipboard.swf" loop="false" menu="false" quality="best" bgcolor="#ffffff" width="0" height="0" name="ZeroClipboardMovie_3" align="middle" allowscriptaccess="always" allowfullscreen="false" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer" flashvars="id=3&width=0&height=0" wmode="transparent"></div></div></div><ol start="1" class="dp-j"><li class="alt"><span><span class="keyword">return</span><span> </span><span class="number">0</span><span>;　</span></span></li><li class=""><span>　 </span></li></ol></div><pre name="code" class="java" style="display: none; ">return 0;} </pre><pre></pre><br><p>翻譯："Pss"， "PrivateDirty"和 "SharedDirty"有什麼區別</p><p>　 Android（亦即Linux）中，大量記憶體實際由多個進程共用，所以一個進程實際佔用多少記憶體並不明確。甚至不太清楚哪些分頁被添加到磁碟。</p><p>　  這樣，要是你要擷取所有實際映射在每個進程的實體記憶體值，然後試圖加總求和，你可能會得到一個遠大於實際記憶體總量的值。</p><p>　  Pss是考慮共用記憶體的核心計算尺度 -- 基本上一個進程的每個記憶體頁面被按一個比率縮減，這個比率和同樣使用該頁面的其他進程的數量有關。理論上你可以累計所有進程的Pss佔用量來檢查所有進程的記憶體佔用量，也可以比較進程的Pss來大致發現進程各自的權重。</p><p>　  另一個有趣的參數是PrivateDirty，它基本上是進程內不能被分頁到磁碟的記憶體，也不和其他進程共用。查看進程的記憶體用量的另一個途徑，就是當進程結束時刻，系統可用記憶體的變化情況（也可能會很快併入高速緩衝或其他使用該記憶體區的進程，[<img alt="微笑" src="http://static.blog.csdn.net/xheditor/xheditor_emot/default/smile.gif">這樣一來，企圖就落空了：-）]）。<br></p><p>原文<br></p><p>But as to what the difference is between "Pss", "PrivateDirty", and "SharedDirty"... well now the fun begins.</p><p>A lot of memory in Android (and Linux systems in general) is actually shared across multiple processes. So how much memory a processes uses is really not clear. Add on top of that paging out to disk (let alone swap which we don't use on Android) and it is even less clear.</p><p>Thus if you were to take all of the physical RAM actually mapped in to each process, and add up all of the processes, you would probably end up with a number much greater than the actual total RAM.</p><p>The Pss number is a metric the kernel computes that takes into account memory sharing -- basically each page of RAM in a process is scaled by a ratio of the number of other processes also using that page. This way you can (in theory) add up the pss across all processes to see the total RAM they are using, and compare pss between processes to get a rough idea of their relative weight.</p><p>The other interesting metric here is PrivateDirty, which is basically the amount of RAM inside the process that can not be paged to disk (it is not backed by the same data on disk), and is not shared with any other processes. Another way to look at this is the RAM that will become available to the system when that process goes away (and probably quickly subsumed into caches and other uses of it).</p><p></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><br>