Question

我正在尝试制作锁定屏幕，因此我在其中包含了BroadcastReceiver和MainActivity中的Service类n。它的工作直到屏幕关闭，当时屏幕正在进行主要活动关闭并显示异常。请帮我解决一下。

MyService.java

package com.example.broadcast_receiver;
import android.app.Service;
...

public class MyService extends Service {

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

    @Override
    public void onCreate() {
        // TODO Auto-generated method stub
        Log.i("[myService]", "onCreate");
        registerReceiver(mybroadcast, new IntentFilter(Intent.ACTION_SCREEN_ON));
        registerReceiver(mybroadcast, new IntentFilter(Intent.ACTION_SCREEN_OFF));
    }

    @Override
    public void onStart(Intent intent, int startId) {
        Toast.makeText(this, "My Service Started", Toast.LENGTH_LONG).show();
        Log.i("[myService]", "onStart");  
    }

    @Override
    public void onDestroy() {
        Toast.makeText(this, "MyService Stopped", Toast.LENGTH_LONG).show();
        Log.i("[myService]", "onDestroy");
    }

    BroadcastReceiver mybroadcast = new BroadcastReceiver(){

        @Override
        public void onReceive(Context context, Intent intent) {
            // TODO Auto-generated method stub
            Log.i("[BroadcastReceiver]", "MyReceiver");

            if(intent.getAction().equals(Intent.ACTION_SCREEN_ON)){
                Log.i("[BroadcastReceiver]", "Screen ON");
                Intent i=new Intent(context, MainActivity.class);
                i.setFlags(Intent.FLAG_ACTIVITY_PREVIOUS_IS_TOP);
                context.startActivity(i);

            }
            else if(intent.getAction().equals(Intent.ACTION_SCREEN_OFF)){
                Log.i("[BroadcastReceiver]", "Screen OFF");
            }
        }

    };
}

MainActivity.java

package com.example.broadcast_receiver;
import android.os.Bundle;
...

public class MainActivity extends Activity {

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

        Log.i("[MainActivity]", "Created");

        try{
        boolean a=isMyServiceRunning();
        if(a==false){
            startService(new Intent(this,MyService.class));
        }
        }catch (Exception e) {
            // TODO: handle exception
            Log.i("Error", e.getMessage().toString());
            Toast.makeText(this, e.getMessage().toString(), Toast.LENGTH_LONG).show();
        }
    }

    private boolean isMyServiceRunning() {
        ActivityManager manager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
        for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
            if (MyService.class.getName().equals(service.service.getClassName())) {
                return true;
            }
        }
        return false;
    }
}

的AndroidManifest.xml （未添加用户许可）

 <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >

         <service android:name="com.example.broadcast_receiver.MyService"
             android:label="@string/app_name"
             android:icon="@drawable/ic_launcher" ></service>

        <activity
            android:name="com.example.broadcast_receiver.MainActivity"
            android:label="@string/app_name"
            android:launchMode="singleTop" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

请帮我解决问题。

Answer 1

该错误告诉您，如果不设置startActivity()，则无法从Activity之外拨打Intent flag NEW_TASK。在致电Intent.FLAG_ACTIVITY_NEW_TASK

之前，将Intent添加到startActivity()

Intent i=new Intent(context, MainActivity.class);
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(i);

从服务启动已经运行的活动

1 个答案: