在内存非常吃紧的情况下，android设备会开始kill部分非系统进程甚至系统进程来保证基本的系统运行。在这种情况下如何获取设备过去某段时间的ram使用情况至关重要。
通过开发者模式中的"内存"可以完美得知设备内存使用信息。
我们可以通过此途径，设计一套通过广播打印内存信息的方式以应对各种调试情况，此文仅将内存信息通过log的形式后台打印获取。
1.发送的广播需要在BroadcastQueue.java特别处理，避免被系统拦截。
2.为了避免各种权限问题，将此套方案耦合在Settings模组。
3.RamInfo参考开发者模式中的方式获取过去某段时间的内存使用情况。
java
Index: frameworks/base/services/core/java/com/android/server/am/BroadcastQueue.java
===================================================================
--- frameworks/base/services/core/java/com/android/server/am/BroadcastQueue.java (版本 10810)
+++ frameworks/base/services/core/java/com/android/server/am/BroadcastQueue.java (版本 10827)
@@ -121,6 +121,7 @@
+ sBackgroundActionWhiteListArraySet.add("com.android.settings.action.RAM_INFO");
}
Index: packages/apps/Settings/src/com/android/settings/applications/RamInfo.java
===================================================================
--- packages/apps/Settings/src/com/android/settings/applications/RamInfo.java (不存在的)
+++ packages/apps/Settings/src/com/android/settings/applications/RamInfo.java (版本 10827)
@@ -0,0 +1,120 @@
+package com.android.settings.applications;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.text.format.Formatter;
+import android.text.format.Formatter.BytesResult;
+import android.util.Log;
+
+import com.android.settings.R;
+import com.android.settings.Utils;
+import com.android.settings.applications.ProcStatsData.MemInfo;
+
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+public class RamInfo extends BroadcastReceiver {
+
+ private static String TAG ="RamInfo";
+
+ private PackageManager mPm;
+
+ @Override
+ public void onReceive(Context context, Intent intent) {
+ Log.d(TAG, "onReceive:" + intent.getAction());
+
+ int index = intent.getIntExtra("index", 3); // 0 - 3h, 1 - 6h, 2 - 12h, 3 - 24h
+
+ mPm = context.getPackageManager();
+
+ ProcStatsData statsManager = new ProcStatsData(context, false);
+ statsManager.setDuration(ProcessStatsBase.sDurations[index]);
+
+ MemInfo memInfo = statsManager.getMemInfo();
+ double usedRam = memInfo.realUsedRam;
+ double totalRam = memInfo.realTotalRam;
+ double freeRam = memInfo.realFreeRam;
+ BytesResult usedResult = Formatter.formatBytes(context.getResources(), (long) usedRam,
+ Formatter.FLAG_SHORTER);
+ String totalString = Formatter.formatShortFileSize(context, (long) totalRam);
+ String freeString = Formatter.formatShortFileSize(context, (long) freeRam);
+ CharSequence memString;
+ CharSequence[] memStatesStr = context.getResources().getTextArray(R.array.ram_states);
+ int memState = statsManager.getMemState();
+ if (memState >= 0 && memState < memStatesStr.length - 1) {
+ memString = memStatesStr[memState];
+ } else {
+ memString = memStatesStr[memStatesStr.length - 1];
+ }
+ String durationString = context.getResources().getString(ProcessStatsBase.sDurationLabels[index]);
+ int numApps = statsManager.getEntries().size();
+
+ Log.d(TAG, "********** RAM INFO (" + durationString + ") **********");
+ // Average
+ Log.d(TAG, context.getResources().getString(R.string.memory_avg_use) + ": " + usedResult.value + usedResult.units);
+ // Performance
+ Log.d(TAG, context.getResources().getString(R.string.memory_performance) + ": " + memString);
+ // Total memory
+ Log.d(TAG, context.getResources().getString(R.string.total_memory) + ": " + totalString);
+ // Average used
+ Log.d(TAG, context.getResources().getString(R.string.average_used) + ": " + (Utils.formatPercentage((long) usedRam, (long) totalRam)));
+ // Free
+ Log.d(TAG, context.getResources().getString(R.string.free_memory) + ": " + freeString);
+ // Memory used by apps
+ Log.d(TAG, context.getResources().getString(R.string.memory_usage_apps)+ ": " + context.getResources().getQuantityString(
+ R.plurals.memory_usage_apps_summary, numApps, numApps, durationString));
+
+ boolean mShowMax = false;
+
+ List<ProcStatsPackageEntry> pkgEntries = statsManager.getEntries();
+
+ // Update everything and get the absolute maximum of memory usage for scaling.
+ for (int i = 0, N = pkgEntries.size(); i < N; i++) {
+ ProcStatsPackageEntry pkg = pkgEntries.get(i);
+ pkg.updateMetrics();
+ }
+
+ Collections.sort(pkgEntries, mShowMax ? sMaxPackageEntryCompare : sPackageEntryCompare);
+
+ for (int i = 0; i < pkgEntries.size(); i++) {
+ ProcStatsPackageEntry pkg = pkgEntries.get(i);
+ pkg.retrieveUiData(context, mPm);
+ boolean statsForeground = pkg.mRunWeight > pkg.mBgWeight;
+ double avgAmount = (statsForeground ? pkg.mRunWeight : pkg.mBgWeight) * memInfo.weightToRam;
+ double maxAmount = (statsForeground ? pkg.mMaxRunMem : pkg.mMaxBgMem) * memInfo.totalScale * 1024;
+ Log.d(TAG, pkg.mUiLabel + "(" + pkg.mPackage + ")" +
+ " {" + context.getResources().getString(R.string.memory_avg_use) + ":" + Formatter.formatShortFileSize(context, (long) avgAmount) + " " +
+ context.getResources().getString(R.string.memory_max_use) + ":" + Formatter.formatShortFileSize(context, (long) maxAmount) + "}");
+ }
+ Log.d(TAG, "********** RAM INFO END **********");
+ }
+
+ final static Comparator<ProcStatsPackageEntry> sPackageEntryCompare
+ = new Comparator<ProcStatsPackageEntry>() {
+ @Override
+ public int compare(ProcStatsPackageEntry lhs, ProcStatsPackageEntry rhs) {
+ double rhsWeight = Math.max(rhs.mRunWeight, rhs.mBgWeight);
+ double lhsWeight = Math.max(lhs.mRunWeight, lhs.mBgWeight);
+ if (lhsWeight == rhsWeight) {
+ return 0;
+ }
+ return lhsWeight < rhsWeight ? 1 : -1;
+ }
+ };
+
+ final static Comparator<ProcStatsPackageEntry> sMaxPackageEntryCompare
+ = new Comparator<ProcStatsPackageEntry>() {
+ @Override
+ public int compare(ProcStatsPackageEntry lhs, ProcStatsPackageEntry rhs) {
+ double rhsMax = Math.max(rhs.mMaxBgMem, rhs.mMaxRunMem);
+ double lhsMax = Math.max(lhs.mMaxBgMem, lhs.mMaxRunMem);
+ if (lhsMax == rhsMax) {
+ return 0;
+ }
+ return lhsMax < rhsMax ? 1 : -1;
+ }
+ };
+}
\ No newline at end of file
Index: packages/apps/Settings/AndroidManifest.xml
===================================================================
--- packages/apps/Settings/AndroidManifest.xml (版本 10810)
+++ packages/apps/Settings/AndroidManifest.xml (版本 10827)
@@ -3603,5 +3603,11 @@
</intent-filter>
</receiver>
+
+ <receiver android:name=".applications.RamInfo">
+ <intent-filter>
+ <action android:name="com.android.settings.action.RAM_INFO" />
+ </intent-filter>
+ </receiver>
</application>
</manifest>