Question

我跟Android Developers tutorial Managing Network Usage了似乎BroadcastReceiver始终与网络断开连接我尝试通过AVD和通过ADB连接的手机运行我的应用，但两者都不起作用。
我还下载了样本，只是复制粘贴以供检查，但似乎有错误我留下了代码但在网站上却是一样的。

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.SharedPreferences;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.webkit.WebView;
import android.widget.Toast;

import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.List;

public class NetworkActivity extends Activity {

    public static final String WIFI = "Wi-Fi";
    public static final String ANY = "Any";
    private static final String FEED_URL = "http://formulapassion.it/feed";

    private static boolean wifiConnected = false;
    private static boolean mobileConnected = false;
    public static boolean refreshDisplay = true;

    public static String sPref = null;

    private NetworkReceiver receiver = new NetworkReceiver();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Filter added dinamically
        IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
        receiver = new NetworkReceiver();
        this.registerReceiver(receiver, filter);
    }

    @Override
    public void onStart() {
        super.onStart();

        SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this);
        sPref = sharedPrefs.getString("listPref", "Wi-Fi");

        updateConnectedFlags();

        if (refreshDisplay) {
            loadPage();
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if (receiver != null) {
            this.unregisterReceiver(receiver);
        }
    }

    private void updateConnectedFlags() {
        ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

        NetworkInfo activeInfo = connMgr.getActiveNetworkInfo();
        if (activeInfo != null && activeInfo.isConnected()) {
            wifiConnected = activeInfo.getType() == ConnectivityManager.TYPE_WIFI;
            mobileConnected = activeInfo.getType() == ConnectivityManager.TYPE_MOBILE;
        } else {
            wifiConnected = false;
            mobileConnected = false;
        }
    }

    private void loadPage() {
        if (((sPref.equals(ANY)) && (wifiConnected || mobileConnected))
                || ((sPref.equals(WIFI)) && (wifiConnected))) {
            new DownloadXmlTask().execute(FEED_URL);
        }
        else {
            showErrorPage();
        }
    }

    private void showErrorPage() {
        setContentView(R.layout.news_feed_webview);

        // The specified network connection is not available. Displays error message.
        WebView myWebView = (WebView) findViewById(R.id.main_webview);
        myWebView.loadData("Errore! Nessuna connessione",
                "text/html", null);
    }

    private class DownloadXmlTask extends AsyncTask<String, Void, String> {
                /* */
    }

    private String loadXmlFromNetwork(String urlString) throws XmlPullParserException, IOException {
                /* */
    }

    public class NetworkReceiver extends BroadcastReceiver {

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

            if (WIFI.equals(sPref) && networkInfo != null
                    && networkInfo.getType() == ConnectivityManager.TYPE_WIFI) {
                refreshDisplay = true;
                Toast.makeText(context, "Connesso", Toast.LENGTH_SHORT).show();
            } else if (ANY.equals(sPref) && networkInfo != null) {
                refreshDisplay = true;
            } else {
                refreshDisplay = false;
                Toast.makeText(context, "Disconnesso", Toast.LENGTH_SHORT).show();
            }

        }
    }
}

和我的Manifest：

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

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

    <uses-sdk xmlns:tools="http://schemas.android.com/tools"
        tools:overrideLibrary="android.support.v14.preference,android.support.v7.appcompat,android.support.v7.preference,android.support.graphics.drawable,android.support.compat,android.support.v4,android.support.coreutils,android.support.mediacompat,android.support.coreui,android.support.fragment,android.support.v7.recyclerview" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/Theme.MyCustomTheme.Light" >
     <!--   android:theme="@style/Theme.AppCompat.Light"> -->

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

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

        <activity
            android:name=".FirstTimeActivity"
            android:theme="@style/Theme.AppCompat.NoActionBar" />

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

        <activity
            android:name=".SettingsActivity"
            android:parentActivityName=".MainActivity" >
                <action android:name="android.intent.action.MANAGE_NETWORK_USAGE" />
                <category android:name="android.intent.category.DEFAULT" />
        </activity>

        <activity android:name=".NetworkActivity">
        </activity>

    </application>

</manifest>

Answer 1

如果您连接到WiFi，则需要添加WiFi状态更改侦听器操作，如下所示：

<receiver android:name=".NetworkActivity$NetworkReceiver">
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
                <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
            </intent-filter>
</receiver>

BroadcastReceiver始终与网络断开连接

1 个答案: