在android listview中添加按钮

Question

嗨，在我的应用程序中，我正在使用 listview，我添加了一些来自 json 的数据，最后我添加了一个按钮，如果我单击按钮，我想移动到另一个活动，但是如果我单击添加按钮，我的应用程序得到了崩溃了。任何人都可以帮助我提前谢谢。

ImageAdapterNew.java：

  public class ImageAdapterNew extends Activity {

        ListView mListView;

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);   


            // URL to the JSON data         
            String strUrl = "http://indianpoliticalleadersmap.com/android/DemoSchool/json/json_item.php";

            // Creating a new non-ui thread task to download json data 
            DownloadTask downloadTask = new DownloadTask();

            // Starting the download process
            downloadTask.execute(strUrl);

            // Getting a reference to ListView of activity_main
            mListView = (ListView) findViewById(R.id.lv_countries);
            mListView.setOnItemClickListener(new OnItemClickListener() {

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

                    Button button1=(Button)findViewById(R.id.add);
                    //String content = ((TextView) view.findViewById(R.id.title)).getText().toString();
                    //Button place = ((Button) view.findViewById(R.id.button2));
                    //String datetime = ((TextView) view.findViewById(R.id.datetime)).getText().toString();
                    button1.setOnClickListener(new View.OnClickListener() {

                        @Override
                        public void onClick(View arg0) {

                            Intent in = new Intent(getApplicationContext(), First.class);
                            startActivity(in);  
                        }
                    });



                    /*in.putExtra(TAG_PLACE, place);
                    *///in.putExtra(TAG_CONTENT, content);
                    //in.putExtra(TAG_DATETIME, datetime);


                }
            });



        }

        /** A method to download json data from url */
        private String downloadUrl(String strUrl) throws IOException{
            String data = "";
            InputStream iStream = null;
            try{
                    URL url = new URL(strUrl);

                    // Creating an http connection to communicate with url 
                    HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

                    // Connecting to url 
                    urlConnection.connect();

                    // Reading data from url 
                    iStream = urlConnection.getInputStream();

                    BufferedReader br = new BufferedReader(new InputStreamReader(iStream));

                    StringBuffer sb  = new StringBuffer();

                    String line = "";
                    while( ( line = br.readLine())  != null){
                        sb.append(line);
                    }

                    data = sb.toString();

                    br.close();

            }catch(Exception e){
                    Log.d("Exception while downloading url", e.toString());
            }finally{
                    iStream.close();
            }

            return data;
        }



        /** AsyncTask to download json data */
        private class DownloadTask extends AsyncTask<String, Integer, String>{
            String data = null;
                    @Override
                    protected String doInBackground(String... url) {
                            try{
                                data = downloadUrl(url[0]);

                            }catch(Exception e){
                                Log.d("Background Task",e.toString());
                            }
                            return data;
                    }

                    @Override
                    protected void onPostExecute(String result) {

                            // The parsing of the xml data is done in a non-ui thread 
                            ListViewLoaderTask listViewLoaderTask = new ListViewLoaderTask();

                            // Start parsing xml data
                            listViewLoaderTask.execute(result);                        

                    }
        }

        /** AsyncTask to parse json data and load ListView */
        private class ListViewLoaderTask extends AsyncTask<String, Void, SimpleAdapter>{

            JSONObject jObject;
            // Doing the parsing of xml data in a non-ui thread 
            @Override
            protected SimpleAdapter doInBackground(String... strJson) {
                try{
                    jObject = new JSONObject(strJson[0]);
                    Schedule1 countryJsonParser = new Schedule1();
                    countryJsonParser.parse(jObject);
                }catch(Exception e){
                    Log.d("JSON Exception1",e.toString());
                }

                // Instantiating json parser class
                Schedule1 countryJsonParser = new Schedule1();

                // A list object to store the parsed countries list
                List<HashMap<String, Object>> schedule = null;

                try{
                    // Getting the parsed data as a List construct
                    schedule = countryJsonParser.parse(jObject);
                }catch(Exception e){
                    Log.d("Exception",e.toString());
                }          

                // Keys used in Hashmap 
                String[] from = { "itemname","image"};

                // Ids of views in listview_layout
                int[] to = { R.id.tv_country,R.id.iv_flag};

                // Instantiating an adapter to store each items
                // R.layout.listview_layout defines the layout of each item         
                SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), schedule, R.layout.lv_layout, from, to);  

                return adapter;
            }

            /** Invoked by the Android on "doInBackground" is executed */
            @Override
            protected void onPostExecute(SimpleAdapter adapter) {

                // Setting adapter for the listview
                mListView.setAdapter(adapter);

                for(int i=0;i<adapter.getCount();i++){
                    HashMap<String, Object> hm = (HashMap<String, Object>) adapter.getItem(i);
                    String imgUrl = (String) hm.get("flag_path");
                    ImageLoaderTask imageLoaderTask = new ImageLoaderTask();

                    HashMap<String, Object> hmDownload = new HashMap<String, Object>();
                    hm.put("flag_path",imgUrl);
                    hm.put("position", i);

                    // Starting ImageLoaderTask to download and populate image in the listview 
                    imageLoaderTask.execute(hm);
                }
            }       
        }

        /** AsyncTask to download and load an image in ListView */
        private class ImageLoaderTask extends AsyncTask<HashMap<String, Object>, Void, HashMap<String, Object>>{

            @Override
            protected HashMap<String, Object> doInBackground(HashMap<String, Object>... hm) {

                InputStream iStream=null;
                String imgUrl = (String) hm[0].get("flag_path");
                int position = (Integer) hm[0].get("position");

                URL url;
                try {
                    url = new URL(imgUrl);

                    // Creating an http connection to communicate with url
                    HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

                    // Connecting to url                
                    urlConnection.connect();

                    // Reading data from url 
                    iStream = urlConnection.getInputStream();

                    // Getting Caching directory 
                    File cacheDirectory = getBaseContext().getCacheDir();

                    // Temporary file to store the downloaded image 
                    File tmpFile = new File(cacheDirectory.getPath() + "/india_"+position+".png");              

                    // The FileOutputStream to the temporary file
                    FileOutputStream fOutStream = new FileOutputStream(tmpFile);

                    // Creating a bitmap from the downloaded inputstream
                    Bitmap b = BitmapFactory.decodeStream(iStream);             

                    // Writing the bitmap to the temporary file as png file
                    b.compress(Bitmap.CompressFormat.PNG,100, fOutStream);              

                    // Flush the FileOutputStream
                    fOutStream.flush();

                    //Close the FileOutputStream
                    fOutStream.close();             

                    // Create a hashmap object to store image path and its position in the listview
                    HashMap<String, Object> hmBitmap = new HashMap<String, Object>();

                    // Storing the path to the temporary image file
                    hmBitmap.put("image",tmpFile.getPath());

                    // Storing the position of the image in the listview
                    hmBitmap.put("position",position);              

                    // Returning the HashMap object containing the image path and position
                    return hmBitmap;                


                }catch (Exception e) {              
                    e.printStackTrace();
                }
                return null;
            }

日志猫：

06-14 16:33:24.274: W/dalvikvm(1592): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
06-14 16:33:24.285: E/AndroidRuntime(1592): FATAL EXCEPTION: main
06-14 16:33:24.285: E/AndroidRuntime(1592): java.lang.IllegalStateException: Could not find a method myClickHandler(View) in the activity class com.example.hotel.ImageAdapterNew for onClick handler on view class android.widget.Button with id 'add'
06-14 16:33:24.285: E/AndroidRuntime(1592):     at android.view.View$1.onClick(View.java:2059)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at android.view.View.performClick(View.java:2408)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at android.view.View$PerformClick.run(View.java:8816)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at android.os.Handler.handleCallback(Handler.java:587)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at android.os.Handler.dispatchMessage(Handler.java:92)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at android.os.Looper.loop(Looper.java:123)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at android.app.ActivityThread.main(ActivityThread.java:4627)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at java.lang.reflect.Method.invokeNative(Native Method)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at java.lang.reflect.Method.invoke(Method.java:521)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at dalvik.system.NativeStart.main(Native Method)
06-14 16:33:24.285: E/AndroidRuntime(1592): Caused by: java.lang.NoSuchMethodException: myClickHandler
06-14 16:33:24.285: E/AndroidRuntime(1592):     at java.lang.ClassCache.findMethodByName(ClassCache.java:308)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at java.lang.Class.getMethod(Class.java:985)
06-14 16:33:24.285: E/AndroidRuntime(1592):     at android.view.View$1.onClick(View.java:2052)
06-14 16:33:24.285: E/AndroidRuntime(1592):     ... 11 more

Answer 1

而不是这个：

Intent in = new Intent(getApplicationContext(), First.class);

这样写：

Intent in = new Intent(ImageAdapterNew.this, First.class);

Answer 2

为什么你把这个点击监听器放在onItemClickListener里面，你需要把它写在外面。

Button button1=(Button)findViewById(R.id.add);
                    //String content = ((TextView) view.findViewById(R.id.title)).getText().toString();
                    //Button place = ((Button) view.findViewById(R.id.button2));
                    //String datetime = ((TextView) view.findViewById(R.id.datetime)).getText().toString();
                    button1.setOnClickListener(new View.OnClickListener() {

                        @Override
                        public void onClick(View arg0) {

                            Intent in = new Intent(ImageAdapterNew.this, First.class);
                            startActivity(in);  
                        }
                    });

Answer 3

首先你应该把你的错误放在 logcat 中，这有助于在你的代码中找到确切的问题

其次，我认为您的按钮来自不同的布局，因此您必须从视图中 finviewbyid。

Button button=(Button)convertView.findViewById(R.layout_inflator.button1);

Answer 4

如果您要在列表的每一行中添加按钮，那么您必须在 getView 方法中添加按钮的 click lisetener。

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    View vi=convertView;
    if(vi==null)
        vi=inflater.inflate(R.layout.catgridres,null);
        Button button=(Button)vi.findViewById(R.layout_inflator.button1);
            button.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View view) {
            //do your code here.
        }

    });
    return vi;
}
For your task I think Custom Adapter is more efficient.