我想使用服务类在弹出窗口中显示自定义列表视图。此列表从数据库中获取数据并在活动中正常工作，但不在弹出窗口中。以下是我的代码。任何帮助将不胜感激。
这是我的服务类：
public class PopupService extends Service{
final static String URL = "https://billspill.com/json.php";
private WindowManager mWindowManager;
private View popupview;
public PopupService() {
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onCreate() {
popupview = LayoutInflater.from(this).inflate(R.layout.popup, null);
//Add the view to the window.
final WindowManager.LayoutParams params = new WindowManager.LayoutParams(
WindowManager.LayoutParams.MATCH_PARENT,
WindowManager.LayoutParams.MATCH_PARENT,
WindowManager.LayoutParams.TYPE_PHONE,
WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
PixelFormat.TRANSLUCENT);
params.gravity = Gravity.TOP | Gravity.START;
params.x = 0;
params.y = 100;
mWindowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
mWindowManager.addView(popupview, params);
Button close = (Button)popupview.findViewById(R.id.dismiss);
close.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
stopSelf();
}
});
ListView lv = (ListView)popupview.findViewById(R.id.pager);
new Downloader(this,lv,URL).execute();
}
@Override
public void onDestroy() {
super.onDestroy();
if (popupview != null) mWindowManager.removeView(popupview);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
return START_NOT_STICKY;
}
下面是我的Downloader类，它扩展了AsyncTask。此Downloader类从DataParser类调用DataParser方法，该方法进一步调用Adapter类以将数据膨胀到列表中。这三个类在一个活动中运行良好，但是当我在我的服务中调用Downloader时，应用程序崩溃了。我认为从服务类传递Downloader中的Context存在问题。
public class Downloader extends AsyncTask<Void,Void,String> {
Context ctx;
ListView lv;
ProgressDialog pd;
@Override
protected void onPreExecute() {
super.onPreExecute();
pd=new ProgressDialog(ctx);
pd.setTitle("Retrive");
pd.setMessage("Retrieving....please wait");
pd.show();
}
@Override
protected void onPostExecute(String jsonData) {
super.onPostExecute(jsonData);
pd.dismiss();
if(jsonData==null)
{
Toast.makeText(ctx,"Unsuccessfull,No data Retrieved",Toast.LENGTH_SHORT).show();
}
else {
DataParser parser = new DataParser(ctx,jsonData,lv);
parser.execute();
}
}
private String downloadData(){
HttpURLConnection con = Connector.connect(urlAddress);
if(con==null) {
Toast.makeText(ctx,"Connection is null",Toast.LENGTH_LONG).show();
}
try{
InputStream is = new BufferedInputStream(con.getInputStream());
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String line;
StringBuffer jsonData= new StringBuffer();
while ((line=br.readLine())!=null)
{
jsonData.append(line+"/n");
}
br.close();
is.close();
return jsonData.toString();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
public Downloader(Context ctx, ListView lv, String urlAddress) {
this.ctx = ctx;
this.lv = lv;
this.urlAddress = urlAddress;
}
String urlAddress;
@Override
protected String doInBackground(Void... params) {
return downloadData();
}
崩溃的开始：
--------- beginning of crash
05-14 18:58:00.694 10664-10664/com.billspillsmoothshopping.android E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.billspillsmoothshopping.android, PID: 10664
java.lang.RuntimeException: Unable to create service com.billspillsmoothshopping.android.PopupService: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
at android.app.ActivityThread.handleCreateService(ActivityThread.java:2771)
at android.app.ActivityThread.access$1800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1386)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)
Caused by: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
at android.view.ViewRootImpl.setView(ViewRootImpl.java:584)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:282)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:85)
at android.app.Dialog.show(Dialog.java:298)
at com.billspillsmoothshopping.android.m_MySQL.CompareDownloader.onPreExecute(CompareDownloader.java:32)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:591)
at android.os.AsyncTask.execute(AsyncTask.java:539)
at com.billspillsmoothshopping.android.PopupService.onCreate(PopupService.java:81)
at android.app.ActivityThread.handleCreateService(ActivityThread.java:2761)
at android.app.ActivityThread.access$1800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1386)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
答案 0 :(得分：0)
您无法附加弹出窗口，其中包含您必须传递实际活动上下文的服务，而不是服务上下文，这是您收到此错误的原因。
我建议你只使用asynctask https://developer.android.com/reference/java/lang/Object.html来获取数据并在服务不那么必要时显示它，如果在下载数据后使用服务太必要，则使用广播接收器将此数据传递给某些活动https://developer.android.com/reference/android/content/BroadcastReceiver.html然后显示弹出窗口。 希望能帮助到你。 附： ＆＃34;我们将服务用于长时间运行的任务，并且没有附加UI，如播放音频，从服务器等下载大数据。＆＃34;