app在無網路情況下非常好判斷，

但是當網路很差，但是又有連結就不好辦了。

使用的retrofit+rxJava，自定義了一個subscribe就可以很好的處理網路差的情況

public class MySubscrible<T> extends Subscriber<HttpResult<T>>  {

    private MySubscribleListener<HttpResult<T>> listener;
    private Context mContext;
//    private Intent intent;
RefreshTask refreshTask
 
;
    private Timer timer;
    public MySubscrible(Context mContext, MySubscribleListener<HttpResult<T>> listener) {
        this.listener = listener;
        this.mContext = mContext;
refreshTask = new RefreshTask();
//        NetWorkManarge.getInstance().registerListtener(this);
}


    @Override
 
public void onStart() {
        super.onStart();
        if (timer == null) {
            timer = new Timer();
timer.scheduleAtFixedRate(refreshTask, 0L, (long) 1000);
}
//        intent = new Intent(mContext, NetWorkService.class);
//        mContext.startService(intent);
}

    @Override
public void onCompleted
 
() {
        listener.onComplete();
        if(timer != null){
            timer.cancel();
timer = null;
}

        Log.i("NetworkSpeedService", "end network test");
}

    @Override
public void onError(Throwable e) {
        LogP.d(e.getMessage());
        if (e instanceof SocketTimeoutException) {
            Toast.makeText(mContext, "網路請求超時，請重試", Toast.LENGTH_SHORT).show();
} else if (e instanceof ConnectException) {
            Toast.makeText(mContext, "網路中斷，請檢查您的網路狀態", Toast.LENGTH_SHORT).show();
} else if (e instanceof NullPointerException) {
            if (listener != null)
                Toast.makeText(mContext, "錯誤，請重試", Toast.LENGTH_SHORT).show();
//            Toast.makeText(mContext, "error:" + e.getMessage(), Toast.LENGTH_SHORT).show();
} else if (e instanceof HttpException) {
            Toast.makeText(mContext, "網路中斷，請檢查您的網路狀態", Toast.LENGTH_SHORT).show();
} else if (e instanceof MyNetWorkSlowException) {
            listener.onNetWorkSlow();
}else if (e instanceof UnknownHostException) {
            Toast.makeText(mContext, "網路錯誤，請檢查您的網路後重試", Toast.LENGTH_SHORT).show();
} else {
//            Toast.makeText(mContext, "error:" + e.getMessage(), Toast.LENGTH_SHORT).show();
Toast.makeText(mContext, "系統錯誤，請重試", Toast.LENGTH_SHORT).show();
}
        this.onCompleted();
}

    @Override
public void onNext(HttpResult<T> httpResult) {
        listener.onNext(httpResult);
}

    public void onNetWorkSlow() {
        this.onError(new MyNetWorkSlowException("networkslow"));
        this.unsubscribe();
}

    class RefreshTask extends TimerTask {
        boolean isFirst = true;
        private Handler handler = new Handler();
        private long rxtxTotal = 0;
        private boolean isNetBad = false;
        private int time;
        private double rxtxSpeed = 1.0f;
        private DecimalFormat showFloatFormat = new DecimalFormat("0.00");
@Override
public void run() {
            isNetBad = false;
            long tempSum = TrafficStats.getTotalRxBytes()
                    + TrafficStats.getTotalTxBytes();
            if (isFirst) {
                rxtxTotal = tempSum;
isFirst = false;
}
            long rxtxLast = tempSum - rxtxTotal;
            double tempSpeed = rxtxLast * 1000 / 1000;
rxtxTotal = tempSum;
            if ((tempSpeed / 1024d) < 20 && (rxtxSpeed / 1024d) < 20) {
                time += 1;
} else {
                time = 0;
}
            rxtxSpeed = tempSpeed;
Log.d("NetworkSpeedService", showFloatFormat.format(tempSpeed / 1024d) + "kb/s");
            if (time >= 16) {//連續16次檢測網速都小於20kb/s  斷定網速很差.
isNetBad = true;
Log.d("NetworkSpeedService", "網速差 " + isNetBad);
time = 0; //重新檢測
}
            if (isNetBad) {
                handler.post(new Runnable() {
                    @Override
public void run() {
//                        receiverIntent.putExtra("is_slow_net_speed", isNetBad);
//                        sendBroadcast(receiverIntent);
//                        NetWorkService.this.stopSelf();
//                        NetWorkManarge.getInstance().notifyLoginData();
MySubscrible.this.onNetWorkSlow();
}
                });
}
        }

    }
}