Monitors main thread for timeouts.

MainThreadWatchDog.java

package io.wondrous.sns.utils;

import android.os.Handler;
import android.os.Looper;

import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;

public class MainThreadWatchDog {
    public static final long MAIN_THREAD_PING_INTERVAL = 200;
    public static final long MAIN_THREAD_TIMEOUT = 500;

    private final Handler mHandler;
    private final AtomicLong mTimestamp = new AtomicLong();
    private final AtomicBoolean mIsStopped = new AtomicBoolean();

    public MainThreadWatchDog(Handler handler) {
        mHandler = handler;
    }

    public void start() {
        mHandler.post(mMainThreadRunnable);
        mThread.start();
    }

    public void stop() {
        mIsStopped.set(true);
    }

    private final Runnable mMainThreadRunnable = new Runnable() {
        @Override
        public void run() {
            mTimestamp.set(System.currentTimeMillis());
            mHandler.postDelayed(this, MAIN_THREAD_PING_INTERVAL);
        }
    };

    private final Thread mThread = new Thread(new Runnable() {
        @Override
        public void run() {
            while (!mIsStopped.get()) {
                try {
                    final long timestamp = mTimestamp.get();
                    final long timeDiff = System.currentTimeMillis() - timestamp;
                    if (timestamp > 0 && timeDiff > MAIN_THREAD_TIMEOUT) {
                        StringBuilder sb = new StringBuilder();
                        sb.append("Main thread timeout (").append(timeDiff).append("ms):\n");

                        StackTraceElement[] stackTrace = Looper.getMainLooper().getThread().getStackTrace();
                        sb.append(printStackTrace(stackTrace));

                        throw new RuntimeException(sb.toString());
                    }
                    Thread.sleep(MAIN_THREAD_TIMEOUT);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    });

    private String printStackTrace(StackTraceElement[] stackTrace) {
        StringBuilder sb = new StringBuilder();
        for (int i = 1; i < stackTrace.length; i++) {
            StackTraceElement s = stackTrace[i];
            sb.append("\tat " + s.getClassName() + "." + s.getMethodName()
                    + "(" + s.getFileName() + ":" + s.getLineNumber() + ")\n");
        }
        return sb.toString();
    }
}