android - AsyncTask 中 ListItem 的 AlertDialog onclick

Question

我想访问 ListItem 的异步任务 onClick 中的警报对话框。以下是我传递给 Activity “getbaseContext()”、“ClassName.this”、“this”的引用；但没有任何效果，它会崩溃。任何想法 ？

异步.java

公共(public)类异步扩展 Activity {

/** Called when the activity is first created. */

ListView _rssFeedListView;
List<JSONObject> jobs;
List<RssFeedStructure> rssStr;
private BlogAdapter _adapter;
TextView textview;
Context context;
AlertDialog.Builder builder
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.listview);

    //context = getApplicationContext();

    _rssFeedListView = (ListView) findViewById(R.id.rssfeed_listview);
     builder = new AlertDialog.Builder(getApplicationContext());
    textview = (TextView) findViewById(R.id.loading);
    RssFeedTask rssTask = new RssFeedTask();
    rssTask.execute();

    _rssFeedListView.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

            //AlertDialog.Builder builder = new AlertDialog.Builder(getApplicationContext());
           // builder.setCancelable(true);
            builder.setTitle("Invitation sent unsuccesful.Please try again !");
          //  builder.setInverseBackgroundForced(true);

            builder.setNegativeButton(
                    "Ok",null

                    );


            builder.show();


        }
    });



}


private class RssFeedTask extends AsyncTask<String, Void, String> {
    // private String Content;
    // private ProgressDialog Dialog;
    String response = "";
    AlertDialog.Builder alert;


    @Override
    protected void onPreExecute() {
    }

    @Override
    protected String doInBackground(String... urls) {
        try {

            String feed = "http://url";
            XmlHandler rh = new XmlHandler();
            rssStr = rh.getLatestArticles(feed);
        } catch (Exception e) {
        }
        return response;

    }

    @Override
    protected void onPostExecute(String result) {
        if (rssStr != null) {

            _adapter = new BlogAdapter(Async.this, rssStr);
            _rssFeedListView.setAdapter(_adapter);
            textview.setVisibility(View.INVISIBLE);


        }


    }

}

}

错误 : 07-31 16:45:56.615: E/AndroidRuntime(28575): FATAL EXCEPTION: main 07-31 16:45:56.615: E/AndroidRuntime(28575): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.view.ViewRootImpl.setView(ViewRootImpl.java:712) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:346) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:224) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:149) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.app.Dialog.show(Dialog.java:277) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.app.AlertDialog$Builder.show(AlertDialog.java:932) 07-31 16:45:56.615: E/AndroidRuntime(28575): at com.itcuties.multicategoryrssreader.BlogFeeds$1.onItemClick(BlogFeeds.java:86) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.widget.AdapterView.performItemClick(AdapterView.java:298) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.widget.AbsListView.performItemClick(AbsListView.java:1283) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.widget.AbsListView$PerformClick.run(AbsListView.java:3074) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.widget.AbsListView$1.run(AbsListView.java:4147) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.os.Handler.handleCallback(Handler.java:615) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.os.Handler.dispatchMessage(Handler.java:92) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.os.Looper.loop(Looper.java:137) 07-31 16:45:56.615: E/AndroidRuntime(28575): at android.app.ActivityThread.main(ActivityThread.java:4898) 07-31 16:45:56.615: E/AndroidRuntime(28575): at java.lang.reflect.Method.invokeNative(Native Method) 07-31 16:45:56.615: E/AndroidRuntime(28575): at java.lang.reflect.Method.invoke(Method.java:511) 07-31 16:45:56.615: E/AndroidRuntime(28575): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008) 07-31 16:45:56.615: E/AndroidRuntime(28575): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775) 07-31 16:45:56.615: E/AndroidRuntime(28575): at dalvik.system.NativeStart.main(Native Method)
Manish & Raji 的建议中收到错误:
07-31 17:53:35.210: E/AndroidRuntime(8442): FATAL EXCEPTION: main 07-31 17:53:35.210: E/AndroidRuntime(8442): android.view.WindowManager$BadTokenException: Unable to add window -- token android.app.LocalActivityManager$LocalActivityRecord@41bdb010 is not valid; is your activity running? 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.view.ViewRootImpl.setView(ViewRootImpl.java:708) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:346) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:224) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:149) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.view.Window$LocalWindowManager.addView(Window.java:554) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.app.Dialog.show(Dialog.java:277) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.app.AlertDialog$Builder.show(AlertDialog.java:932) 07-31 17:53:35.210: E/AndroidRuntime(8442): at com.itcuties.multicategoryrssreader.BlogFeeds$1.onItemClick(BlogFeeds.java:78) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.widget.AdapterView.performItemClick(AdapterView.java:298) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.widget.AbsListView.performItemClick(AbsListView.java:1283) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.widget.AbsListView$PerformClick.run(AbsListView.java:3074) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.widget.AbsListView$1.run(AbsListView.java:4147) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.os.Handler.handleCallback(Handler.java:615) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.os.Handler.dispatchMessage(Handler.java:92) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.os.Looper.loop(Looper.java:137) 07-31 17:53:35.210: E/AndroidRuntime(8442): at android.app.ActivityThread.main(ActivityThread.java:4898) 07-31 17:53:35.210: E/AndroidRuntime(8442): at java.lang.reflect.Method.invokeNative(Native Method) 07-31 17:53:35.210: E/AndroidRuntime(8442): at java.lang.reflect.Method.invoke(Method.java:511) 07-31 17:53:35.210: E/AndroidRuntime(8442): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008) 07-31 17:53:35.210: E/AndroidRuntime(8442): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775) 07-31 17:53:35.210: E/AndroidRuntime(8442): at dalvik.system.NativeStart.main(Native Method)

Answer 1

在调用异步类之前初始化上下文。