Android Studio threaded debugging

Question

I've been having trouble debugging a multithreaded app with Android Studio 1.1. It seems as if when a breakpoint is hit all other threads also stop, not just the one with the breakpoint. I created a simple test app with the following method in the Activity's onCreate.

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Thread a = new Thread("thread-a") {
        @Override
        public void run() {
            Log.v("thread", "thread-a");
        }
    };

    Thread b = new Thread("thread-b") {
        @Override
        public void run() {
            Log.v("thread", "thread-b");
        }
    };

    a.start();
    b.start();
}

I set breakpoints at the Log.v lines in thread-a and thread-b and then I run it in debug mode on my Lollipop Nexus 5.

When the app starts it hits the breakpoint in thread-a but the first problem I notice is that the app's UI is blank as if the main thread is paused. Next I went to see that the breakpoint in thread-b is also hit so I pull up the Threads view in Android Studio's debugger but when I go to expand the thread-b arrow there's nothing there. When I expand the main thread it shows it is paused somewhere in onStart().

Am I doing something wrong or is this debugger incapable of debugging multiple threads at once?

Answer 1

In IntelliJ IDEA (and Android Studio is based on IntelliJ), when you place a breakpoint, if you do right click over it a dialog is displayed and you can select whether to pause all threads (the default) or only that thread.

You are pausing all the threads as it is the default setting.