There is a blog post from Square on how to spy for Looper
's queue: https://corner.squareup.com/2013/12/android-main-thread-2.html
Here is how they do it for main Looper
:
public class MainLooperSpy {
private final Field messagesField;
private final Field nextField;
private final MessageQueue mainMessageQueue;
public MainLooperSpy() {
try {
Field queueField = Looper.class.getDeclaredField("mQueue");
queueField.setAccessible(true);
messagesField = MessageQueue.class.getDeclaredField("mMessages");
messagesField.setAccessible(true);
nextField = Message.class.getDeclaredField("next");
nextField.setAccessible(true);
Looper mainLooper = Looper.getMainLooper();
mainMessageQueue = (MessageQueue) queueField.get(mainLooper);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public void dumpQueue() {
try {
Message nextMessage = (Message) messagesField.get(mainMessageQueue);
Log.d("MainLooperSpy", "Begin dumping queue");
dumpMessages(nextMessage);
Log.d("MainLooperSpy", "End dumping queue");
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
}
}
public void dumpMessages(Message message) throws IllegalAccessException {
if (message != null) {
Log.d("MainLooperSpy", message.toString());
Message next = (Message) nextField.get(message);
dumpMessages(next);
}
}
}