android - 广播接收器未调用互联网连接检查

Question

我正在尝试制作一个简单的应用程序，它会在互联网连接发生变化时通知是否有可用的互联网连接。我在互联网上找到了一些解决方案并尝试实现它们，但不知何故它不起作用。我在 list 文件中注册的广播接收器未调用网络连接更改。

list

 <uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<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">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

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

    <receiver
        android:name=".NetworkStateChangeReceiver">
        <intent-filter >
            <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
        </intent-filter>
    </receiver>

</application>

广播接收器

package com.gdm.internetconnectivitycheck;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;

import static android.content.Context.CONNECTIVITY_SERVICE;

public class NetworkStateChangeReceiver extends BroadcastReceiver {

public static final String NETWORK_AVAILABLE_ACTION = "com.gdm.retailalfageek.NetworkAvailable";
public static final String IS_NETWORK_AVAILABLE = "isNetworkAvailable";

@Override
public void onReceive(Context context, Intent intent) {
    Intent networkStateIntent = new Intent(NETWORK_AVAILABLE_ACTION);
    networkStateIntent.putExtra(IS_NETWORK_AVAILABLE,  isConnectedToInternet(context));
    LocalBroadcastManager.getInstance(context).sendBroadcast(networkStateIntent);
    Log.e("Network Available ", "On receive called");
}

private boolean isConnectedToInternet(Context context) {
    try {
        if (context != null) {
            ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(CONNECTIVITY_SERVICE);
            NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
            return networkInfo != null && networkInfo.isConnected();
        }
        return false;
    } catch (Exception e) {
        Log.e(NetworkStateChangeReceiver.class.getName(), e.getMessage());
        return false;
    }
}
}

主要 Activity

package com.gdm.internetconnectivitycheck;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.support.v4.content.LocalBroadcastManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.design.widget.Snackbar;

import static com.gdm.internetconnectivitycheck.NetworkStateChangeReceiver.IS_NETWORK_AVAILABLE;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    IntentFilter intentFilter = new IntentFilter(NetworkStateChangeReceiver.NETWORK_AVAILABLE_ACTION);
    LocalBroadcastManager.getInstance(this).registerReceiver(new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            boolean isNetworkAvailable = intent.getBooleanExtra(IS_NETWORK_AVAILABLE, false);
            String networkStatus = isNetworkAvailable ? "connected" : "disconnected";

            Snackbar.make(findViewById(R.id.main_activity), "Network Status: " + networkStatus, Snackbar.LENGTH_LONG).show();

        }
    }, intentFilter);


}
}

Answer 1

Apps targeting Android 7.0 (API level 24) and higher must register the following broadcasts with

registerReceiver(BroadcastReceiver,IntentFilter)

Declaring a receiver in the manifest does not work.

CONNECTIVITY_ACTION

Beginning with Android 8.0 (API level 26), the system imposes additional restrictions on manifest-declared receivers. If your app targets API level 26 or higher, you cannot use the manifest to declare a receiver for most implicit broadcasts (broadcasts that do not target your app specifically). You can still use a context-registered reciever when the user is actively using your app.

直接来自官方doc .

您需要在运行时从 Activity 中注册 CONNECTIVITY_CHANGE 操作。使用 registerReceiver。

IntentFilter filter = new IntentFilter();
filter.addAction("android.net.conn.CONNECTIVITY_CHANGE");
registerReceiver(new NetworkStateChangeReceiver(), filter);

不要忘记注销。