禁用触摸并显示正在加载的gif图像

Question

我希望在服务检查没有互联网连接时禁用屏幕并显示进度对话框 这是我的代码

public class Wifiservice extends Service {
public static final int notify = 5000;  //interval between two services(Here Service run every 5 Minute)
private Handler mHandler = new Handler();   //run on another Thread to avoid crash
private Timer mTimer = null;    //timer handling
public static final int alert_notify = 50;  //interval between two services(Here Service run every 5 Minute)
private Handler alert_mHandler = new Handler();   //run on another Thread to avoid crash
private Timer alert_mTimer = null;    //timer handling
AlertDialog dialog;
@Override
public IBinder onBind(Intent intent) {
    throw new UnsupportedOperationException("Not yet implemented");
}

@Override
public void onCreate() {
    if (mTimer != null) // Cancel if already existed
        mTimer.cancel();
    else
        mTimer = new Timer();
    dialog = new AlertDialog.Builder(Wifiservice.this).create();
    //recreate new
    mTimer.scheduleAtFixedRate(new TimeDisplay(), 0, notify);   //Schedule task

    if (alert_mTimer != null) // Cancel if already existed
        alert_mTimer.cancel();
    else
        alert_mTimer = new Timer();
    //recreate new
    alert_mTimer.scheduleAtFixedRate(new hide_alert_box(), 0, alert_notify);   //Schedule task
}

@Override
public void onDestroy() {
    super.onDestroy();
    mTimer.cancel();    //For Cancel Timer
}

//class TimeDisplay for handling task
class TimeDisplay extends TimerTask {
    @Override
    public void run() {
        // run on another thread
        mHandler.post(new Runnable() {
            @Override
            public void run() {

                if(!isAppIsInBackground(getApplicationContext())) {
                    boolean flage = GlobalClass.isDeviceOnline(getApplicationContext());
                    if (!flage && GlobalClass.wififlage == 1) {
                        GlobalClass.wififlage = 0;
                        dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_TOAST);
                        dialog.getWindow().setGravity(Gravity.CENTER);
                        dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
                        LayoutInflater factory = LayoutInflater.from(Wifiservice.this);
                        final View view = factory.inflate(R.layout.activity_waiting_for__network, null);
                        dialog.setView(view);
                        dialog.setOnCancelListener(new DialogInterface.OnCancelListener() {
                            @Override
                            public void onCancel(DialogInterface dialogInterface) {
                                if(!isAppIsInBackground(getApplicationContext())) {
                                    if (!GlobalClass.isDeviceOnline(getApplicationContext())) {
                                        dialog.show();
                                    }
                                }
                                else{
                                    GlobalClass.wififlage = 1;
                                }
                            }
                        });
                        dialog.show();
                    } else if (flage && GlobalClass.wififlage == 0) {
                        GlobalClass.wififlage = 1;
                        dialog.cancel();
                    }
                }
            }
        });
    }
}




class hide_alert_box extends TimerTask {
    @Override
    public void run() {
        alert_mHandler.post(new Runnable() {
            @Override
            public void run() {
                if(isAppIsInBackground(getApplicationContext())) {
                    GlobalClass.wififlage = 1;
                    dialog.cancel();
                }
            }
        });
    }
}


private boolean isAppIsInBackground(Context context) {
    boolean isInBackground = true;
    ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    if (Build.VERSION.SDK_INT > Build.VERSION_CODES.KITKAT_WATCH) {
        List<ActivityManager.RunningAppProcessInfo> runningProcesses = am.getRunningAppProcesses();
        for (ActivityManager.RunningAppProcessInfo processInfo : runningProcesses) {
            if (processInfo.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
                for (String activeProcess : processInfo.pkgList) {
                    if (activeProcess.equals(context.getPackageName())) {
                        isInBackground = false;
                    }
                }
            }
        }
    } else {
        List<ActivityManager.RunningTaskInfo> taskInfo = am.getRunningTasks(1);
        ComponentName componentInfo = taskInfo.get(0).topActivity;
        if (componentInfo.getPackageName().equals(context.getPackageName())) {
            isInBackground = false;
        }
    }

    return isInBackground;
}

}

显示以下错误，而不是应用崩溃

Process: , PID: 20161
android.view.WindowManager$BadTokenException: Unable to add window android.view.ViewRootImpl$W@1511bfc -- permission denied for window type 2003
    at android.view.ViewRootImpl.setView(ViewRootImpl.java:914)
    at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:377)
    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:97)
    at android.app.Dialog.show(Dialog.java:404)
    at com.houzcalls.services.Wifiservice$TimeDisplay$1.run(Wifiservice.java:106)
    at android.os.Handler.handleCallback(Handler.java:751)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6776)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1518)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1408)