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>
增加一个广播接收器，可以监听网络连接的变化。然后使用ConnectivityManager检查设备是否连接到internet。详情请参考这篇文章或视频。下面是代码:
public class NetworkStateChangeReceiver extends BroadcastReceiver {
public static final String NETWORK_AVAILABLE_ACTION = "com.ajit.singh.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);
}
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;
}
}
}
我写这个接收器是为了在屏幕上显示通知，这就是为什么你会看到一个带有网络状态的本地广播。下面是显示通知的代码。
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.activity_main), "Network Status: " + networkStatus, Snackbar.LENGTH_LONG).show();
}
}, intentFilter);
}
}
活动监听网络接收器广播的意图，并在屏幕上显示通知。
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 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。
增加一个广播接收器，可以监听网络连接的变化。然后使用ConnectivityManager检查设备是否连接到internet。详情请参考这篇文章或视频。下面是代码:
public class NetworkStateChangeReceiver extends BroadcastReceiver {
public static final String NETWORK_AVAILABLE_ACTION = "com.ajit.singh.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);
}
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;
}
}
}
我写这个接收器是为了在屏幕上显示通知，这就是为什么你会看到一个带有网络状态的本地广播。下面是显示通知的代码。
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.activity_main), "Network Status: " + networkStatus, Snackbar.LENGTH_LONG).show();
}
}, intentFilter);
}
}
活动监听网络接收器广播的意图，并在屏幕上显示通知。
检查网络状态:
private void checkInternetConnection() {
if (br == null) {
br = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
Bundle extras = intent.getExtras();
NetworkInfo info = (NetworkInfo) extras
.getParcelable("networkInfo");
State state = info.getState();
Log.d("TEST Internet", info.toString() + " "
+ state.toString());
if (state == State.CONNECTED) {
Toast.makeText(getApplicationContext(), "Internet connection is on", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(), "Internet connection is Off", Toast.LENGTH_LONG).show();
}
}
};
final IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver((BroadcastReceiver) br, intentFilter);
}
}
记得在onDestroy中注销服务。
干杯! !
