本篇博文在我之前的博文中已经提到了,可是监听Activity切换又能够作为一个单独的内容来叙述,因此这里又单独拿了出来进行赘述。
Activity的切换无非有两种。第一种:启动或者创建一个新的Activity;另外一种:唤醒后台执行的Activity。
因此假设我们可以成功监听到启动或者创建一个Activity,或者唤醒Activity我们就基本完毕了Activity的切换的监听。
在源代码/frameworks/base/core/java/android/app文件夹下ActivityThread.java中为我们提供了这样一个方法来帮助我们完毕对Activity启动、创建、销毁、暂停、停止。唤醒等生命周期的监听。
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public void handleMessage(Message msg) {
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if (DEBUG_MESSAGES) Slog.v(TAG, ">>> handling: " + codeToString(msg.what));
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switch (msg.what) {
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case LAUNCH_ACTIVITY: {
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if ( true == mEnableAppLaunchLog && !mIsUserBuild && false == mTraceEnabled ) {
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try {
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FileInputStream fprofsts_in = new FileInputStream("/proc/mtprof/status");
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if ( fprofsts_in.read()== ‘3‘ ) {
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Log.v(TAG, "start Profiling for empty process");
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mTraceEnabled = true;
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Debug.startMethodTracing("/data/data/applaunch");
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}
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} catch (FileNotFoundException e) {
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Slog.e(TAG, "mtprof entry can not be found", e);
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} catch (java.io.IOException e) {
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Slog.e(TAG, "mtprof entry open failed", e);
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}
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}
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER | Trace.TRACE_TAG_PERF, "activityStart");
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ActivityClientRecord r = (ActivityClientRecord)msg.obj;
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r.packageInfo = getPackageInfoNoCheck(
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r.activityInfo.applicationInfo, r.compatInfo);
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handleLaunchActivity(r, null);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER | Trace.TRACE_TAG_PERF);
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} break;
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case RELAUNCH_ACTIVITY: {
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityRestart");
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ActivityClientRecord r = (ActivityClientRecord)msg.obj;
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handleRelaunchActivity(r);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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} break;
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case PAUSE_ACTIVITY:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityPause");
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handlePauseActivity((IBinder)msg.obj, false, msg.arg1 != 0, msg.arg2);
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maybeSnapshot();
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case PAUSE_ACTIVITY_FINISHING:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityPause");
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handlePauseActivity((IBinder)msg.obj, true, msg.arg1 != 0, msg.arg2);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case STOP_ACTIVITY_SHOW:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityStop");
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handleStopActivity((IBinder)msg.obj, true, msg.arg2);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case STOP_ACTIVITY_HIDE:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityStop");
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handleStopActivity((IBinder)msg.obj, false, msg.arg2);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case SHOW_WINDOW:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityShowWindow");
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handleWindowVisibility((IBinder)msg.obj, true);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case HIDE_WINDOW:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityHideWindow");
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handleWindowVisibility((IBinder)msg.obj, false);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case RESUME_ACTIVITY:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER | Trace.TRACE_TAG_PERF, "activityResume");
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handleResumeActivity((IBinder)msg.obj, true,
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msg.arg1 != 0, true);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER | Trace.TRACE_TAG_PERF);
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break;
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case SEND_RESULT:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityDeliverResult");
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handleSendResult((ResultData)msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case DESTROY_ACTIVITY:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityDestroy");
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handleDestroyActivity((IBinder)msg.obj, msg.arg1 != 0,
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msg.arg2, false);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case BIND_APPLICATION:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "bindApplication");
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AppBindData data = (AppBindData)msg.obj;
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handleBindApplication(data);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case EXIT_APPLICATION:
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if (mInitialApplication != null) {
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mInitialApplication.onTerminate();
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}
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Looper.myLooper().quit();
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break;
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case NEW_INTENT:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityNewIntent");
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handleNewIntent((NewIntentData)msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case RECEIVER:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "broadcastReceiveComp");
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handleReceiver((ReceiverData)msg.obj);
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maybeSnapshot();
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case CREATE_SERVICE:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "serviceCreate");
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handleCreateService((CreateServiceData)msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case BIND_SERVICE:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "serviceBind");
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handleBindService((BindServiceData)msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case UNBIND_SERVICE:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "serviceUnbind");
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handleUnbindService((BindServiceData)msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case SERVICE_ARGS:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "serviceStart");
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handleServiceArgs((ServiceArgsData)msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case STOP_SERVICE:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "serviceStop");
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handleStopService((IBinder)msg.obj);
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maybeSnapshot();
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case REQUEST_THUMBNAIL:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "requestThumbnail");
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handleRequestThumbnail((IBinder)msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case CONFIGURATION_CHANGED:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "configChanged");
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mCurDefaultDisplayDpi = ((Configuration)msg.obj).densityDpi;
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handleConfigurationChanged((Configuration)msg.obj, null);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case CLEAN_UP_CONTEXT:
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ContextCleanupInfo cci = (ContextCleanupInfo)msg.obj;
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cci.context.performFinalCleanup(cci.who, cci.what);
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break;
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case GC_WHEN_IDLE:
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scheduleGcIdler();
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break;
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case DUMP_SERVICE:
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handleDumpService((DumpComponentInfo)msg.obj);
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break;
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case LOW_MEMORY:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "lowMemory");
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handleLowMemory();
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case ACTIVITY_CONFIGURATION_CHANGED:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityConfigChanged");
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handleActivityConfigurationChanged((IBinder)msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case PROFILER_CONTROL:
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handleProfilerControl(msg.arg1 != 0, (ProfilerControlData)msg.obj, msg.arg2);
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break;
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case CREATE_BACKUP_AGENT:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backupCreateAgent");
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handleCreateBackupAgent((CreateBackupAgentData)msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case DESTROY_BACKUP_AGENT:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backupDestroyAgent");
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handleDestroyBackupAgent((CreateBackupAgentData)msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case SUICIDE:
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Process.killProcess(Process.myPid());
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break;
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case REMOVE_PROVIDER:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "providerRemove");
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completeRemoveProvider((ProviderRefCount)msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case ENABLE_JIT:
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ensureJitEnabled();
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break;
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case DISPATCH_PACKAGE_BROADCAST:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "broadcastPackage");
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handleDispatchPackageBroadcast(msg.arg1, (String[])msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case SCHEDULE_CRASH:
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throw new RemoteServiceException((String)msg.obj);
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case DUMP_HEAP:
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handleDumpHeap(msg.arg1 != 0, (DumpHeapData)msg.obj);
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break;
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case DUMP_ACTIVITY:
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handleDumpActivity((DumpComponentInfo)msg.obj);
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break;
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case DUMP_PROVIDER:
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handleDumpProvider((DumpComponentInfo)msg.obj);
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break;
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case SLEEPING:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "sleeping");
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handleSleeping((IBinder)msg.obj, msg.arg1 != 0);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case SET_CORE_SETTINGS:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "setCoreSettings");
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handleSetCoreSettings((Bundle) msg.obj);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case UPDATE_PACKAGE_COMPATIBILITY_INFO:
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handleUpdatePackageCompatibilityInfo((UpdateCompatibilityData)msg.obj);
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break;
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case TRIM_MEMORY:
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Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "trimMemory");
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handleTrimMemory(msg.arg1);
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Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
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break;
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case UNSTABLE_PROVIDER_DIED:
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handleUnstableProviderDied((IBinder)msg.obj, false);
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break;
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case REQUEST_ASSIST_CONTEXT_EXTRAS:
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handleRequestAssistContextExtras((RequestAssistContextExtras)msg.obj);
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break;
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case TRANSLUCENT_CONVERSION_COMPLETE:
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handleTranslucentConversionComplete((IBinder)msg.obj, msg.arg1 == 1);
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break;
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case INSTALL_PROVIDER:
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handleInstallProvider((ProviderInfo) msg.obj);
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break;
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}
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if (DEBUG_MESSAGES) Slog.v(TAG, "<<< done: " + codeToString(msg.what));
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if(!mIsUserBuild && isDebuggableMessage(msg.what)){
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Slog.d(TAG, codeToString(msg.what) + " handled "
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+ ": " + msg.arg1 + " / " + msg.obj);
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}
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}
这里我们能够看到。我们能够通过监听LAUNCH_ACTIVITY,RESUME_ACTIVITY等来推断Activity的切换,因此我们能够将通过在ActivityThread.java中将获得顶层栈栈顶Activity的方法在这里调用以实现我们的需求。
那么这样是否可以完毕我们的需求呢?
答案是否定的。即使我们可以编译通过,可是在我们測试观察log的时候。并不能得到当前处于活动状态的Activity。那么为什么会出现这样的情况呢?
通过观察log我们发现,这里我们须要GET_TASK权限,当然我们能够通过加入权限的方式,但这样有风险,那么有没有一个更可靠的方式呢。
依然是通过观察log,我们发现Android系统会使用一个ActivityClientRecoder类来记录Activity的信息,而这个类在ActivityThread中也得到了应用。因此我们能够通过得到ActivityClientRecoder的对象r来获得Activity对象,在通过Activity对象的getComponent()来得到ComponentName的对象。在ComponentName对象中便封装了应用程序包名和当前处于活动状态的Activity。
详细实现方式这里不再详细赘述。仅仅是提供获取Activity信息的部分代码进行简单分析一下,大家能够參考一下。
ActivityClientRecord r = (ActivityClientRecord)msg.obj;
Activity a=r.parent;
ComponentName c=a.getComponentName();
String package=c.mPackage;
String className=c.mClass;StrSt
此外另一种备用的方式,就是我们能够通过得到当前处于活动状态进程信息来推断当前处以活动状态的进程。
实现方式例如以下:
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final ActivityManager am = (ActivityManager)mAppContextImpl.getSystemService(Context.ACTIVITY_SERVICE);
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List<RunningAppProcessInfo> list = am.getRunningAppProcesses();
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if (list.size() != 0) {
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RunningAppProcessInfo topRunningProcess = list.get(0);
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if(topRunningProcess.processName.equals("com.android.xx.xxxxx")){
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return true;
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}
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}
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return false;