Android使用BroadcastReceiver监听网络连接状态的改变

以下是使用BroadcastReceiver监听网络连接状态改变的完整攻略：

1. 在AndroidManifest.xml文件中添加权限和声明BroadcastReceiver：

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

<receiver
    android:name=\".NetworkChangeReceiver\"
    android:enabled=\"true\"
    android:exported=\"true\">
    <intent-filter>
        <action android:name=\"android.net.conn.CONNECTIVITY_CHANGE\" />
    </intent-filter>
</receiver>

1. 创建NetworkChangeReceiver类并继承BroadcastReceiver：

public class NetworkChangeReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        if (ConnectivityManager.CONNECTIVITY_ACTION.equals(intent.getAction())) {
            ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
            if (networkInfo != null && networkInfo.isConnected()) {
                // 网络已连接
                Toast.makeText(context, \"网络已连接\", Toast.LENGTH_SHORT).show();
            } else {
                // 网络断开连接
                Toast.makeText(context, \"网络已断开\", Toast.LENGTH_SHORT).show();
            }
        }
    }
}

示例说明1：注册BroadcastReceiver

NetworkChangeReceiver receiver = new NetworkChangeReceiver();
IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(receiver, filter);

示例说明2：取消注册BroadcastReceiver

unregisterReceiver(receiver);

以上是使用BroadcastReceiver监听网络连接状态改变的完整攻略。通过注册BroadcastReceiver并在onReceive()方法中处理网络连接状态的改变，您可以实时获取网络连接状态的变化并做出相应的处理。