我正在开发一个用于检查互联网连接的android广播接收器。

问题是我的广播接收器被调用了两次。我希望它只在网络可用时被调用。如果它不可用,我不想被通知。

这是广播接收机

public class NetworkChangeReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(final Context context, final Intent intent) {
        final ConnectivityManager connMgr = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);

        final android.net.NetworkInfo wifi = connMgr
                .getNetworkInfo(ConnectivityManager.TYPE_WIFI);

        final android.net.NetworkInfo mobile = connMgr
                .getNetworkInfo(ConnectivityManager.TYPE_MOBILE);

        if (wifi.isAvailable() || mobile.isAvailable()) {
            // Do something

            Log.d("Network Available ", "Flag No 1");
        }
    }
}

这是manifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.broadcastreceiverforinternetconnection"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <receiver android:name=".NetworkChangeReceiver" >
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
                <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
            </intent-filter>
        </receiver>
    </application>

</manifest>

当前回答

CONNECTIVITY_ACTION文档:

针对Android 7.0 (API级别24)及以上的应用程序,如果它们在manifest中声明了广播接收器,则不会接收此广播。如果应用程序向context . registerreceiver()注册了BroadcastReceiver,并且该context仍然有效,那么应用程序仍然会接收广播。

其他回答

public static boolean isNetworkAvailable(Context context) {
        boolean isMobile = false, isWifi = false;

        NetworkInfo[] infoAvailableNetworks = getConnectivityManagerInstance(
                context).getAllNetworkInfo();

        if (infoAvailableNetworks != null) {
            for (NetworkInfo network : infoAvailableNetworks) {

                if (network.getType() == ConnectivityManager.TYPE_WIFI) {
                    if (network.isConnected() && network.isAvailable())
                        isWifi = true;
                }
                if (network.getType() == ConnectivityManager.TYPE_MOBILE) {
                    if (network.isConnected() && network.isAvailable())
                        isMobile = true;
                }
            }
        }

        return isMobile || isWifi;
    }

/* You can write such method somewhere in utility class and call it NetworkChangeReceiver like below */
public class NetworkChangedReceiver extends BroadcastReceiver 
{
@Override
    public void onReceive(Context context, Intent intent) {

        if (isNetworkAvailable(context)) 
                {
             Toast.makeText(context, "Network Available Do operations",Toast.LENGTH_LONG).show(); 


    }
    }
}

只有当网络状态变为已连接而不是已断开时,才会调用上述广播接收器。

回答第一个问题:您的广播接收器被调用了两次,因为

您已经添加了两个<intent-filter>

网络连接的改变: <action android:name="android.net.conn.CONNECTIVITY_CHANGE" /> WiFi状态变化: <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />

就用一个: <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />。

它将只响应一个操作而不是两个。更多信息请参见这里。

回答你的第二个问题(如果可以上网,你想让对方只打一次电话):

你的代码是完美的;只有在互联网可用时才通知。

更新

如果你只是想检查手机是否与互联网相连,你可以使用这种方法来检查你的连接。

public boolean isOnline(Context context) {

    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netInfo = cm.getActiveNetworkInfo();
    //should check null because in airplane mode it will be null
    return (netInfo != null && netInfo.isConnected());
}
public class AsyncCheckInternet extends AsyncTask<String, Void, Boolean> {

public static final int TIME_OUT = 10 * 1000;

private OnCallBack listener;

public interface OnCallBack {

    public void onBack(Boolean value);
}

public AsyncCheckInternet(OnCallBack listener) {
    this.listener = listener;
}

@Override
protected void onPreExecute() {
}

@Override
protected Boolean doInBackground(String... params) {

    ConnectivityManager connectivityManager = (ConnectivityManager) General.context
            .getSystemService(Context.CONNECTIVITY_SERVICE);

    NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();

    if ((networkInfo != null && networkInfo.isConnected())
            && ((networkInfo.getType() == ConnectivityManager.TYPE_WIFI) || (networkInfo
                    .getType() == ConnectivityManager.TYPE_MOBILE))) {
        HttpURLConnection urlc;
        try {
            urlc = (HttpURLConnection) (new URL("http://www.google.com")
                    .openConnection());
            urlc.setConnectTimeout(TIME_OUT);
            urlc.connect();
            if (urlc.getResponseCode() == HttpURLConnection.HTTP_OK) {
                return true;
            } else {
                return false;
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
            return false;

        } catch (IOException e) {
            e.printStackTrace();
            return false;

        }
    } else {
        return false;
    }
}

@Override
protected void onPostExecute(Boolean result) {
    if (listener != null) {
        listener.onBack(result);
    }
}

}

这里有一种适合活动、片段或上下文的方法。它也会自动注销,如果你做的活动/片段(在onDestroy),如果你希望:

abstract class ConnectionBroadcastReceiver : BroadcastReceiver() {
    companion object {
        @JvmStatic
        fun registerWithoutAutoUnregister(context: Context, connectionBroadcastReceiver: ConnectionBroadcastReceiver) {
            context.registerReceiver(connectionBroadcastReceiver, IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION))
        }

        @JvmStatic
        fun registerToFragmentAndAutoUnregister(context: Context, fragment: Fragment, connectionBroadcastReceiver: ConnectionBroadcastReceiver) {
            val applicationContext = context.applicationContext
            registerWithoutAutoUnregister(applicationContext, connectionBroadcastReceiver)
            fragment.lifecycle.addObserver(object : LifecycleObserver {
                @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)
                fun onDestroy() {
                    applicationContext.unregisterReceiver(connectionBroadcastReceiver)
                }
            })
        }

        @JvmStatic
        fun registerToActivityAndAutoUnregister(activity: AppCompatActivity, connectionBroadcastReceiver: ConnectionBroadcastReceiver) {
            registerWithoutAutoUnregister(activity, connectionBroadcastReceiver)
            activity.lifecycle.addObserver(object : LifecycleObserver {
                @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)
                fun onDestroy() {
                    activity.unregisterReceiver(connectionBroadcastReceiver)
                }
            })
        }

        @JvmStatic
        fun hasInternetConnection(context: Context): Boolean {
            val info = (context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager).activeNetworkInfo
            return !(info == null || !info.isConnectedOrConnecting)
        }
    }

    override fun onReceive(context: Context, intent: Intent) {
        val hasConnection = !intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY, false)
//        Log.d("AppLog", "conenctivity changed. hasConnection? $hasConnection")
        onConnectionChanged(hasConnection)
    }

    abstract fun onConnectionChanged(hasConnection: Boolean)
}

在片段中的用法:

    ConnectionBroadcastReceiver.registerToFragmentAndAutoUnregister(activity!!, this, object : ConnectionBroadcastReceiver() {
        override fun onConnectionChanged(hasConnection: Boolean) {
            // Log.d("AppLog", "onConnectionChanged:" + hasConnection)
        }
    })

1)在manifest: -调用接收器如下代码

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.safal.checkinternet">

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        tools:ignore="AllowBackup,GoogleAppIndexingWarning">
        <receiver android:name=".NetworkChangeReceiver" >
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
            </intent-filter>
        </receiver>
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

2)创建一个宽播接收器类:在这个类中添加网络检查的代码

package com.safal.checkinternet;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.util.Log;
import android.widget.Toast;

public class NetworkChangeReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(final Context context, final Intent intent) {
        if (isOnline(context)){
            Toast.makeText(context, "Available", Toast.LENGTH_SHORT).show();
        }else {
            Toast.makeText(context, "Not Available", Toast.LENGTH_SHORT).show();
        }
    }
    public boolean isOnline(Context context) {

        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        assert cm != null;
        NetworkInfo netInfo = cm.getActiveNetworkInfo();
        return (netInfo != null && netInfo.isConnected());
    }    
} 

3)在您的活动中呼叫广播接收器:-

package com.safal.checkinternet;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
//Call Broad cast Receiver 
        IntentFilter filter = new IntentFilter();
        filter.addAction("android.net.conn.CONNECTIVITY_CHANGE");
        registerReceiver(new NetworkChangeReceiver(), filter);
    }
}