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施它们,但不知何故它不起作用。我在清单文件中注册的广播接收器没有调用网络连接更改。
Manifest
<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;
}
}
}
主要活动
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);
}
}
针对 Android 7.0(API 级别 24)及更高版本的应用程序必须注册
以下广播
registerReceiver(BroadcastReceiver,IntentFilter)
在清单中声明接收者不起作用。
连接性_操作
从 Android 8.0(API 级别 26)开始,
系统对清单声明的接收者施加了额外的限制。
如果您的应用程序以 API 级别 26 或更高级别为目标,则无法使用
清单以声明大多数隐式广播的接收者
(不专门针对您的应用程序的广播)。你仍然可以
当用户主动使用您的服务时,使用上下文注册的接收器
应用程序。
直接来自官方doc https://developer.android.com/guide/components/broadcasts.
您需要在运行时从活动注册 CONNECTIVITY_CHANGE 操作。
使用注册接收者.
IntentFilter filter = new IntentFilter();
filter.addAction("android.net.conn.CONNECTIVITY_CHANGE");
registerReceiver(new NetworkStateChangeReceiver(), filter);
并且不要忘记注销。
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