Question

我正在开发一个Android应用程序，其中在特定时间间隔后再次触发操作，当收到 Intent.FLAG_ACTIVITY_NEW_TASK 广播消息时再次触发。我在 UpdateService.java ：

中有以下代码

package com.missnoob.screentimeout;

import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;

public class UpdateService extends Service {

    @Override
    public void onCreate() {
        super.onCreate();
        // REGISTER RECEIVER THAT HANDLES SCREEN ON AND SCREEN OFF LOGIC
        IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
        filter.addAction(Intent.ACTION_SCREEN_OFF);
        BroadcastReceiver mReceiver = new ScreenReceiver();
        registerReceiver(mReceiver, filter);
    }

    @Override
    public void onStart(Intent intent, int startId) {
        boolean screenOn = intent.getBooleanExtra("screen_state", false);
        if (!screenOn) {
            Log.v("ScreenTimeOut","Broadcast Received");
            Toast.makeText(getApplicationContext(), "Broadcast Received", Toast.LENGTH_LONG).show();

            //This part is not working
            Intent i = new Intent(this, Notification.class);
            i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            //This part is not working

        } 
        else 
        {
            // YOUR CODE
        }
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO Auto-generated method stub
        return null;
    }
}

Notification.java 中的以下代码：

package com.missnoob.screentimeout;

import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;
import com.shadow.screentimeout.R;

public class Notification extends Activity {
/** Called when the activity is first created. */

Timer timer;
Toast toast;

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

    timer = new Timer();
    toast = Toast.makeText(getApplicationContext(), "15 seconds after",Toast.LENGTH_SHORT);

    timer.scheduleAtFixedRate(new TimerTask() 
        {
            @Override
            public void run() {
                toast.show();
                Log.v("ScreenTimeOut","Toast showed");

            }
        }, 0, 5000);

    }

}

在 UpdateService.java

中

Intent i = new Intent(this, Notification.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

永远不会被触发。

Answer 1

您缺少startActivity(i)

 Intent i = new Intent(this, Notification.class);
 i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
 startActivity(i);

你也不能

 toast.show();

在计时器中，因为它在不同的线程上运行，你只能在ui线程上更新ui。

而是使用Handler。你可以找到一个例子@

Android Thread for a timer

Answer 2

您尚未拨打startActivity(i)。

请参阅Start Another Activity（android开发者网站）。

Answer 3

你没有打电话给startActivity(i)，这就是为什么你的活动从未被召唤过，你所要做的就是这样：

 Intent i = new Intent(this, Notification.class);
 i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
 startActivity(i);

永远不会调用Activity

3 个答案: