[英]How to start an animation immediately on activity launch without any start delay
[英]How to Launch BraodCastReceiver in Android without any Activity?
我想在打開內置設備 Wi-Fi 時顯示 Toast 消息,而不是通過活動中的任何按鈕。 我的目標是制作一個不創建任何啟動器但在后台工作的應用程序。 我試過了,但仍然沒有任何吐司。 我的接收器類在這里:
public class Receiver extends BroadcastReceiver {
@Override
public void onReceive(final Context context, final Intent intent) {
String status = NetworkUtil.getConnectivityStatusString(context);
Toast.makeText(context, status, Toast.LENGTH_LONG).show();
}
}
我的 NetworkUtil 類在這里:
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)
return TYPE_WIFI;
if(activeNetwork.getType() == ConnectivityManager.TYPE_MOBILE)
return TYPE_MOBILE;
}
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;
}
}
我的 Manifest.xml 就像這里:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="net.xyz.network"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<receiver
android:name="net.xyz.network.Receiver"
android:label="Receiver" >
<intent-filter>
<action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
<action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
</intent-filter>
</receiver>
</application>
</manifest>
我在這里犯了什么錯誤導致它不輸出?
嘗試
Toast.makeText(context.getApplicationContext(), status, Toast.LENGTH_LONG).show();
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