如何获取Android 7.0主线程的堆栈跟踪？

Question

作为Android 7.0上的简单测试，Thread.getAllStackTraces() API无法获取主线程（属于“主”线程组）的堆栈跟踪。但是主线程的堆栈轨迹可以通过Thread.currentThread().getStackTrace()得到。

测试代码：

Number of threads get by 'Thread.getAllStackTraces()': 10 
[ID]: 1871, [Name]: GCDaemon 
[ID]: 1867, [Name]: ReferenceQueueDaemon 
[ID]: 1870, [Name]: HeapTrimmerDaemon 
[ID]: 1872, [Name]: Binder_1 
[ID]: 1866, [Name]: JDWP 
[ID]: 1868, [Name]: FinalizerDaemon 
[ID]: 1869, [Name]: FinalizerWatchdogDaemon 
[ID]: 1, [Name]: main 
[ID]: 1873, [Name]: Binder_2 
[ID]: 1865, [Name]: Signal Catcher 
Current thread name: main 
Current group name: main 
main stack element[0]: dalvik.system.VMStack.getThreadStackTrace(Native Method) 
main stack element[1]: java.lang.Thread.getStackTrace(Thread.java:580) 
main stack element[2]: com.test.demo.MainActivity.onCreate(MainActivity.java:169) 
main stack element[3]: android.app.Activity.performCreate(Activity.java:6117) 
main stack element[4]: android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1123) 
main stack element[5]: android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2612) 
main stack element[6]: android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2728) 
main stack element[7]: android.app.ActivityThread.access$800(ActivityThread.java:179) 
main stack element[8]: android.app.ActivityThread$H.handleMessage(ActivityThread.java:1579) 
main stack element[9]: android.os.Handler.dispatchMessage(Handler.java:111) 
main stack element[10]: android.os.Looper.loop(Looper.java:194) 
main stack element[11]: android.app.ActivityThread.main(ActivityThread.java:5838) 
main stack element[12]: java.lang.reflect.Method.invoke(Native Method) 
main stack element[13]: java.lang.reflect.Method.invoke(Method.java:372) 
main stack element[14]: com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1009) 
main stack element[15]: com.android.internal.os.ZygoteInit.main(ZygoteInit.java:804) 

结果在Android 7.0：

Number of threads get by 'Thread.getAllStackTraces()': 4 
[ID]: 116, [Name]: FinalizerWatchdogDaemon 
[ID]: 114, [Name]: ReferenceQueueDaemon 
[ID]: 115, [Name]: FinalizerDaemon 
[ID]: 117, [Name]: HeapTaskDaemon 
Current thread name: main 
Current group name: main 
main stack element[0]: dalvik.system.VMStack.getThreadStackTrace(Native Method) 
main stack element[1]: java.lang.Thread.getStackTrace(Thread.java:1566) 
main stack element[2]: com.test.demo.MainActivity.onCreate(MainActivity.java:169) 
main stack element[3]: android.app.Activity.performCreate(Activity.java:6664) 
main stack element[4]: android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118) 
main stack element[5]: android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599) 
main stack element[6]: android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) 
main stack element[7]: android.app.ActivityThread.-wrap12(ActivityThread.java) 
main stack element[8]: android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) 
main stack element[9]: android.os.Handler.dispatchMessage(Handler.java:102) 
main stack element[10]: android.os.Looper.loop(Looper.java:154) 
main stack element[11]: android.app.ActivityThread.main(ActivityThread.java:6077) 
main stack element[12]: java.lang.reflect.Method.invoke(Native Method) 
main stack element[13]: com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) 
main stack element[14]: com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755) 

这看起来像是相对与Android的许可才能获得Android 4.4的

Set<Thread> threads = Thread.getAllStackTraces().keySet(); 
    Log.d("Test", String.format("Number of threads get by 'Thread.getAllStackTraces()': %d", threads.size())); 
    for (Thread thread : threads) { 
     if (thread != null) { 
      Log.d("Test", String.format("[ID]: %d, [Name]: %s", thread.getId(), thread.getName())); 
     } 
    } 
    Log.d("Test", String.format("Current thread name: %s", Thread.currentThread().getName())); 
    Log.d("Test", String.format("Current group name: %s", Thread.currentThread().getThreadGroup().getName())); 
    StackTraceElement[] elements = Thread.currentThread().getStackTrace(); 
    for (int i = 0; i < elements.length; i++) { 
     Log.d("Test", String.format("main stack element[%d]: %s", i, elements[i])); 
    } 

结果线程信息。但Android设备监视器可以获取所有线程及其详细信息。

那么有没有什么办法可以让主线程堆栈在android = 7.0上？

感谢您的阅读和解答。

Answer 1

我可以证实，无论出于何种原因，显然getAllStackTraces()都不会为主UI线程提供堆栈跟踪。但是，有一种方法：在任何后台线程中，您可以调用Looper.getMainLooper().getThread().getStackTrace()（或者只需记住UI代码中的某个Thread对象，然后在该代码上调用getStackTrace()）。

你也许在做一些性能分析？我尝试过Android监视器，它比无用的更糟糕 - 不仅UI非常慢，而且捕获完全不匹配的错误堆栈痕迹！我正在考虑编写一个非常简单的吮吸式分析器，您可以随意启动和停止，只需将分析详细信息转储到Android控制台即可。