检查与广播接收机的连接

Question

我在项目中工作，需要检查互联网连接并在后台做一些事情，但它不起作用。这是代码

public class NetworkChangeReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if (ConnectivityManager.CONNECTIVITY_ACTION.equals(intent.getAction())) {
Toast.makeText(context, "Connectivity changed", Toast.LENGTH_SHORT).show();
}
}
}

---

清单：

<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" />

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

Answer 1

使用此

ConnectivityReceiver.java

public class ConnectivityReceiver
extends BroadcastReceiver {
public static ConnectivityReceiverListener connectivityReceiverListener;
public ConnectivityReceiver() {
super();
}
@Override
public void onReceive(Context context, Intent arg1) {
ConnectivityManager cm = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
boolean isConnected = activeNetwork != null
&& activeNetwork.isConnectedOrConnecting();
if (connectivityReceiverListener != null) {
connectivityReceiverListener.onNetworkConnectionChanged(isConnected);
}
}
public static boolean isConnected() {
ConnectivityManager
cm = (ConnectivityManager) MyApplication.getInstance().getApplicationContext()
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
return activeNetwork != null
&& activeNetwork.isConnectedOrConnecting();
}

public interface ConnectivityReceiverListener {
void onNetworkConnectionChanged(boolean isConnected);
}
}

MyApplication.java

public class MyApplication extends Application {
private static MyApplication mInstance;
@Override
public void onCreate() {
super.onCreate();
mInstance = this;
}
public static synchronized MyApplication getInstance() {
return mInstance;
}
public void setConnectivityListener(ConnectivityReceiver.ConnectivityReceiverListener listener) {
ConnectivityReceiver.connectivityReceiverListener = listener;
}
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<application
android:name=".MyApplication"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity"
android:label="@string/app_name"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver
android:name=".ConnectivityReceiver"
android:enabled="true">
<intent-filter>
<action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
</intent-filter>
</receiver>
</application>

主要活动.java

public class MainActivity extends AppCompatActivity
implements ConnectivityReceiver.ConnectivityReceiverListener {
private Button btnCheck;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
btnCheck = (Button) findViewById(R.id.btn_check);
// Manually checking internet connection
checkConnection();
btnCheck.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// Manually checking internet connection
checkConnection();
}
});
}
// Method to manually check connection status
private void checkConnection() {
boolean isConnected = ConnectivityReceiver.isConnected();
showSnack(isConnected);
}
// Showing the status in Snackbar
private void showSnack(boolean isConnected) {
String message;
int color;
if (isConnected) {
message = "Good! Connected to Internet";
color = Color.WHITE;
} else {
message = "Sorry! Not connected to internet";
color = Color.RED;
}
Snackbar snackbar = Snackbar
.make(findViewById(R.id.fab), message, Snackbar.LENGTH_LONG);
View sbView = snackbar.getView();
TextView textView = (TextView) sbView.findViewById(android.support.design.R.id.snackbar_text);
textView.setTextColor(color);
snackbar.show();
}
@Override
protected void onResume() {
super.onResume();
// register connection status listener
MyApplication.getInstance().setConnectivityListener(this);
}
/**
* Callback will be triggered when there is change in
* network connection
*/
@Override
public void onNetworkConnectionChanged(boolean isConnected) {
showSnack(isConnected);
}
}