Question

我正在尝试在ListView的setOnItemClickListner中使用image.setOnClickListener，但它崩溃了，任何想法？或者可以在AsyncTask的onPostExecute中使用它。我这样做的原因是这个图像与我在AsyncTask的onPostExecute中定义的LayoutInflater相关联，所以我必须只保留图像按钮。

错误：

08-02 15:52:12.829: E/AndroidRuntime(32221): FATAL EXCEPTION: main
08-02 15:52:12.829: E/AndroidRuntime(32221): java.lang.NullPointerException
08-02 15:52:12.829: E/AndroidRuntime(32221):    at com.itcuties.multicategoryrssreader.BlogFeeds$RssFeedTask$1.onItemClick(BlogFeeds.java:103)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at android.widget.AdapterView.performItemClick(AdapterView.java:298)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at android.widget.AbsListView.performItemClick(AbsListView.java:1283)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at android.widget.AbsListView$PerformClick.run(AbsListView.java:3074)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at android.widget.AbsListView$1.run(AbsListView.java:4147)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at android.os.Handler.handleCallback(Handler.java:615)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at android.os.Handler.dispatchMessage(Handler.java:92)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at android.os.Looper.loop(Looper.java:137)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at android.app.ActivityThread.main(ActivityThread.java:4898)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at java.lang.reflect.Method.invokeNative(Native Method)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at java.lang.reflect.Method.invoke(Method.java:511)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775)
08-02 15:52:12.829: E/AndroidRuntime(32221):    at dalvik.system.NativeStart.main(Native Method)

Popup.java

public class Popup extends Activity {

    ListView _rssFeedListView;
List<JSONObject> jobs;
List<RssFeedStructure> rssStr;
private BlogAdapter _adapter;
TextView textview;

    @Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.listview);
    _rssFeedListView = (ListView) findViewById(R.id.rssfeed_listview);

    textview = (TextView) findViewById(R.id.loading);
    RssFeedTask rssTask = new RssFeedTask();
    rssTask.execute();

}

private class RssFeedTask extends AsyncTask<String, Void, String> {

    String response = "";
    ImageView image = (ImageView) findViewById(R.id.closebutton);
    PopupWindow popupWindow;

    @Override
    protected void onPreExecute() {
    }

    @Override
    protected String doInBackground(String... urls) {
        try {
            String feed = "http://someurl";
            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(Popup.this, rssStr);
            _rssFeedListView.setAdapter(_adapter);
            textview.setVisibility(View.INVISIBLE);

            _rssFeedListView.setOnItemClickListener(new OnItemClickListener() {

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

                            LayoutInflater layoutInflater = (LayoutInflater)getBaseContext().getSystemService(LAYOUT_INFLATER_SERVICE);  
                            View layout = layoutInflater.inflate(R.layout.new_popup_layout, null);  
                            popupWindow = new PopupWindow(layout, LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
                            WebView web = (WebView)layout.findViewById(R.id.webView1);

                            ImageView image = (ImageView) findViewById(R.id.closebutton);

                            web.getSettings().setJavaScriptEnabled(true);
                            web.getSettings().setLoadWithOverviewMode(true);
                            web.getSettings().setDefaultFontSize(10);
                            web.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);
                            web.setScrollbarFadingEnabled(true);

                            String text = "<html><body style=\"text-align:justify\"> %s </body></Html>";
                            String summary = rssStr.get(position).getEncodedContent();

                            Log.d("String", summary);
                            web.loadDataWithBaseURL(null, String.format(text, summary), "text/html", "UTF-8",null);
                            popupWindow.showAtLocation(view,Gravity.CENTER, 0, 0);

                            image.setOnClickListener(new OnClickListener() {
                                public void onClick(View v)
                                {
                                    popupWindow.dismiss(); 
                                } 

                            });

                        }

            });

        }

    }

}

}

new_popup_layout.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">

 <TableRow
    android:id="@+id/tableRow1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="right" >

    <ImageView
        android:id="@+id/closebutton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@android:drawable/btn_dialog" />
</TableRow>


<WebView
    android:id="@+id/webView1"
    android:layout_width="match_parent"
    android:layout_height="480dp"/>

</LinearLayout>

Answer 1

您需要在自定义适配器的getView（）内为imageView定义单击侦听器，即image.setOnClickListener。

Answer 2

imageView在new_popup_layout.xml中定义，但您使用了setContentView(R.layout.listview)。它无法在指定的layout.xml中找到该imageview。所以返回null

请看一次这件事。

如何在ListView的setOnItemClickListener中使用image.setOnClickListener - Android

2 个答案: