Question

我正在尝试使用以下代码扩展Activity来广播Toast消息。但是另一个Activity没有收到广播，不显示吐司。有人可以解决我的错误吗？主要活动是 SendBroadcast.java

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;

public class SendBroadcast extends Activity {

    public static String BROADCAST_ACTION =
                             "com.unitedcoders.android.broadcasttest.SHOWTOAST";

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

    public void sendBroadcast(View v) {
        Intent broadcast = new Intent();
        broadcast.setAction(BROADCAST_ACTION);
        sendBroadcast(broadcast);
    }
}

Toast Display Activity ToastDisplay.java

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.widget.Toast;

public class ToastDisplay extends Activity {

    private BroadcastReceiver receiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
            Toast.makeText(getApplicationContext(), "received",
                    Toast.LENGTH_SHORT).show();
        }
    };

    @Override
    protected void onResume() {
        IntentFilter filter = new IntentFilter();
        filter.addAction(SendBroadcast.BROADCAST_ACTION);
        registerReceiver(receiver, filter);
        super.onResume();
    }

    @Override
    protected void onPause() {
        unregisterReceiver(receiver);
        super.onPause();
    }
}

和 manifest.xml 如下

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.broad"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-sdk android:minSdkVersion="3" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:name=".SendBroadcast"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <receiver android:name=".ToastReceiver" >
            <intent-filter>
                <action android:name="com.unitedcoders.android.broadcasttest.SHOWTOAST" />
            </intent-filter>
        </receiver>
    </application>
</manifest>

Answer 1

可以有两种类型的broacast：静态和动态。静态是在清单文件中声明的那些。动态可以在运行时声明。您将这两种类型的广播合并为一个广播。

要声明简单的动态广播，您可以使用以下代码（基于您的代码）。它只会在显示活动时显示Toast消息。

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

public class BroadcastTestActivity extends Activity {

    public static String BROADCAST_ACTION =     
                            "com.unitedcoders.android.broadcasttest.SHOWTOAST";
    BroadcastReceiver br = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
            Log.w("Check", "Inside On Receiver");
            Toast.makeText(getApplicationContext(), "received",
                    Toast.LENGTH_SHORT).show();
        }
    };

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        IntentFilter filter = new IntentFilter();
        filter.addAction(BROADCAST_ACTION);
        filter.addCategory(Intent.CATEGORY_DEFAULT);
        registerReceiver(br, filter);
    }

    @Override
    protected void onResume() {
        super.onResume();
        sendBroadcast();
    }

    @Override
    protected void onPause() {
        super.onPause();
        unregisterReceiver(br);
    }

    public void sendBroadcast() {
        Intent broadcast = new Intent();
        broadcast.setAction(BROADCAST_ACTION);
        broadcast.addCategory(Intent.CATEGORY_DEFAULT);
        sendBroadcast(broadcast);
    }
}

现在，您可以调用新活动，而不是显示吐司。以下操作取决于您的需求（您想要做什么）。

Answer 2

ToastReceiver类在哪里？

<receiver android:name=".ToastReceiver">
    <intent-filter>
        <action android:name="com.unitedcoders.android.broadcasttest.SHOWTOAST"/>
</intent-filter>
</receiver>`

更改

public class ToastDisplay extends Activity {
    private BroadcastReceiver receiver = new BroadcastReceiver() {

}

到

public class ToastReceiver extends BroadcastReceiver {

}

Answer 3

尝试

<activity android:name=".SendBroadcast" android:label="@string/app_name">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
    <intent-filter>
        <action android:name="android.intent.action.BROADCAST" />
    </intent-filter>
</activity>

在onCreate()电话

中

sendBroadcast(v);

Answer 4

Button b1 = (Button)findViewById(R.id.button1);

b1.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View arg0) {
        try {
            String RESULT = new TestAsyncTask().execute(" ").get();
            System.out.println("RESULT "+RESULT);
        } 
        catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
        catch (ExecutionException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
});

BroadcastReceiver未接收广播

4 个答案: