Question

我的[0] => Array ( [name] => Cash crops ) [1] => Array ( [name] => Pulse crops ) [2] => Array ( [name] => Oil seed crops ) [3] => Array ( [name] => Cereal Crops )中有BroadcastReceiver个班级。我想从接收器类开始Activity。我可以从写入接收器的同一Fragment调用它吗？

Answer 1

是的，您可以使用LocalBroadCastManger

来完成

import android.app.Activity;
import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.IBinder;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;
import android.view.View;
import android.widget.Button;

public class LocalBroadcastExampleActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.log_list);

        Button buttonStartService = (Button)findViewById(R.id.button_ok);
        buttonStartService.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                //Register MessageService in Manifest to work
                startService(new Intent(LocalBroadcastExampleActivity.this, MessageService.class));
            }
        });

    }

    @Override
    protected void onPause() {
        // Unregister since the activity is paused.
        LocalBroadcastManager.getInstance(this).unregisterReceiver(
                mMessageReceiver);
        super.onPause();
    }

    @Override
    protected void onResume() {
        // Register to receive messages.
        // We are registering an observer (mMessageReceiver) to receive Intents
        // with actions named "custom-event-name".
        LocalBroadcastManager.getInstance(this).registerReceiver(
                mMessageReceiver, new IntentFilter("custom-event-name"));
        super.onResume();
    }

    // Our handler for received Intents. This will be called whenever an Intent
    // with an action named "custom-event-name" is broadcasted.
    private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            // TODO Auto-generated method stub
            // Get extra data included in the Intent
            String message = intent.getStringExtra("message");
            Log.d("receiver", "Got message: " + message);
        }
    };

    public class MessageService extends Service {

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

        @Override
        public int onStartCommand(Intent intent, int flags, int startId) {
            // TODO Auto-generated method stub
            sendMessage();
            return super.onStartCommand(intent, flags, startId);
        }

        // Send an Intent with an action named "custom-event-name". The Intent
        // sent should
        // be received by the ReceiverActivity.
        private void sendMessage() {
            Log.d("sender", "Broadcasting message");
            Intent intent = new Intent("custom-event-name");
            // You can also include some extra data.
            intent.putExtra("message", "This is my message!");
            LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
        }

    }

}

Answer 2

尝试这样的事情......如果您使用自定义广播接收器，则将此类替换为接收者类的广播接收。

public class Demo extends AppCompatActivity {
    private final IntentFilter filter = new IntentFilter();
    private BroadcastReceiver networkStateReceiver;

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

    @Override
    public void onResume() {
        super.onResume();
        // Defining broadcast receiver in onResume() 
        networkStateReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
               //Do what you want
            }
        };
        // Registering receiver with intent filter, here intent filter can be changed
        filter.addAction("android.net.conn.CONNECTIVITY_CHANGE");
        registerReceiver(networkStateReceiver, filter);
    }

    @Override
    protected void onPause() {
       super.onPause();
       // Unregister receiver in onStop to avoid any runtime exception
       unregisterReceiver(networkStateReceiver);
   }
}

是否可以从写入接收器的同一个Activity调用BroadcastReceiver？

2 个答案: