我是android的初学者，我在internet.xml中添加了2个图标
，基于网络连接（例如是否已连接网络）
应显示已连接图标，否则应显示未连接图标
在工具栏上），为此我在以下位置创建了onPrepareOptionsMenu（）
活动以及BroadcastReceiver来广播当前网络
状态，因为图标必须动态更改。
在这里我使用了Intent来广播当前的网络状态，它是
再次重新启动活动，我不知道该如何打电话
BroadcastReceiver类中的onPrepareOptionsMenu（）
根据网络自动更新工具栏中的菜单项
状态。
谁能帮助我做到这一点？
**ConnectionActivity**
public class ConnectionActivity extends AppCompatActivity {
Menu menu;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_parser);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.internet, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
boolean online = false;
MenuItem netMenuItem = menu.findItem(R.id.network_signal);
MenuItem nonetMenuItem = menu.findItem(R.id.network_signal_off);
int status = NetworkUtil.getConnectivityStatus(this);
if (status == 1 || status == 2)
online = true;
else
online = false;
netMenuItem.setVisible(online);
nonetMenuItem.setVisible(!online);
return true;
}
}
**NetworkUtil.java**
public class NetworkUtil {
public static int TYPE_WIFI = 1;
public static int TYPE_MOBILE = 2;
public static int TYPE_NOT_CONNECTED = 0;
public static int getConnectivityStatus(Context context) {
ConnectivityManager cm = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
if (null != activeNetwork) {
if (activeNetwork.getType() == ConnectivityManager.TYPE_WIFI) {
Log.d("WIFI CONNECTED", activeNetwork.getType() + "");
return TYPE_WIFI;
}
if (activeNetwork.getType() == ConnectivityManager.TYPE_MOBILE) {
Log.d("MOBILE CONNECTED", activeNetwork.getType() + "");
return TYPE_MOBILE;
}
}
Log.d("NOT CONNECTED", TYPE_NOT_CONNECTED + "");
return TYPE_NOT_CONNECTED;
}
public static String getConnectivityStatusString(Context context) {
int conn = NetworkUtil.getConnectivityStatus(context);
String status = null;
if (conn == NetworkUtil.TYPE_WIFI) {
status = "Wifi enabled";
} else if (conn == NetworkUtil.TYPE_MOBILE) {
status = "Mobile data enabled";
} else if (conn == NetworkUtil.TYPE_NOT_CONNECTED) {
status = "Not connected to Internet";
}
return status;
}
}
**NetworkChangeReceiver**
public class NetworkChangeReceiver extends BroadcastReceiver {
@RequiresApi(api = Build.VERSION_CODES.KITKAT)
@Override
public void onReceive(Context context, Intent intent) {
String status = NetworkUtil.getConnectivityStatusString(context);
Toast.makeText(context, status, Toast.LENGTH_LONG).show();
Intent activityIntent = new Intent(context, ParserActivity.class);
activityIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(activityIntent);
}
}
**Menifest.xml**
<receiver
android:name=".NetworkChangeReceiver"
android:enabled="true"
android:exported="false">
<intent-filter>
<action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
<action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
</intent-filter>
</receiver>
**internet.xml**
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<item
android:title="signal_off"
android:id="@+id/network_signal_off"
android:icon="@drawable/ic_signal_wifi_off_black_24dp"
app:showAsAction="always"></item>
<item
android:id="@+id/network_signal"
android:icon="@drawable/ic_signal_wifi_4_bar_black_24dp"
android:title="Signal"
app:showAsAction="always"></item>
</menu>
最佳答案
还有另一种方法，而不是通过调用onPrepareOptionsMenu
public class NetworkChangeReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
try {
if (isOnline(context)) {
// show online icon
ConnectionActivity.setMenuVisible(true);
} else {
// show offline icon
ConnectionActivity.setMenuVisible(false);
}
} catch (Exception e) {
e.printStackTrace();
}
}
private boolean isOnline(Context context) {
try {
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());
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
}
================================================== ==========================
public class ConnectionActivity extends AppCompatActivity {
Menu menu;
private BroadcastReceiver mNetworkReceiver;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_parser);
mNetworkReceiver = new NetworkChangeReceiver();
registerReceiver(mNetworkReceiver, new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.internet, menu);
this.menu = menu;
this.menu.findItem(R.id.network_signal).setVisible(false);
this.menu.findItem(R.id.network_signal_off).setVisible(false);
return super.onCreateOptionsMenu(menu);
}
public static void setMenuVisible(boolean isOnline) {
if (isOnline) {
if (menu != null) {
menu.findItem(R.id.network_signal).setVisible(true);
menu.findItem(R.id.network_signal_off).setVisible(false);
}
} else {
if (menu != null) {
menu.findItem(R.id.network_signal_off).setVisible(true);
menu.findItem(R.id.network_signal).setVisible(false);
}
}
}
private void unregisterNetworkChanges() {
try {
unregisterReceiver(mNetworkReceiver);
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void onDestroy() {
super.onDestroy();
unregisterNetworkChanges();
}
}