hashmap 在 simpleadapter 中工作，但在自定义数组适配器中不工作 [英] hashmap working in simpleadapter but not working in custom array adapter

问题描述

下面代码的 Hashmap 适用于 simpleadapter 数组，但不适用于自定义数组适配器.为什么?我该如何解决?请帮助.无法解决.尝试了一切.

Hashmap for the code below is working for simpleadapter array but not for custom array adapter .Why ? and how do I fix it ? Please Help.Unable to resolve .Tried everything.

我正在使用lazyLoading 类来加载图像.

I am using lazyLoading class to load images.

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


                HashMap<String, String> o = (HashMap<String, String>) list.getItemAtPosition(position);
                Toast.makeText(CustomizedListView.this, "ID '" + o.get("KEY_TITLE") + "' was clicked.", Toast.LENGTH_SHORT).show(); 

            }        

上面显示的 onclick 崩溃的整个代码:

The entire code which is crashing at onclick shown above :

public class CustomizedListView extends Activity {
    // All static variables
    static final String URL = "https://itunes.apple.com/us/rss/topalbums/limit=20/json";
    // XML node keys
    static final String KEY_SONG = "song"; // parent node
    static final String KEY_ID = "id";
    static final String KEY_TITLE = "title";
    static final String KEY_ARTIST = "artist";
    static final String KEY_DURATION = "duration";
    static final String KEY_THUMB_URL = "thumb_url";

    ListView list;
    LazyAdapter adapter;

    HashMap<String, String> map;


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


        ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();

        JSONObject json = JSONfunctions.getJSONfromURL(URL);


        try {
            JSONObject arr2 = json.getJSONObject("feed");
            JSONArray arr = arr2.getJSONArray("entry");

            for (int i = 0; i < arr.length(); i++) {
                JSONObject e1 = arr.getJSONObject(i);

                JSONArray arr3 = e1.getJSONArray("im:image");

                JSONObject arr8 = e1.getJSONObject("im:name");

                JSONObject arr10 = e1.getJSONObject("im:artist");

                    JSONObject e12 = arr3.getJSONObject(0);

            // creating new HashMap
             map = new HashMap<String, String>();

            map.put(KEY_THUMB_URL,  e12.getString("label"));

            map.put(KEY_ARTIST, arr8.getString("label"));
            map.put(KEY_TITLE, arr10.getString("label"));
            // adding HashList to ArrayList
            songsList.add(map);
            }

        } catch (JSONException e) {
            // Log.e("log_tag", "Error parsing data "+e.toString());
            Toast.makeText(getBaseContext(),
                    "Network communication error!", 5).show();
        }


        list=(ListView)findViewById(R.id.list);

        // Getting adapter by passing xml data ArrayList
        adapter=new LazyAdapter(this, songsList);        
        list.setAdapter(adapter);

        // Click event for single list row
        list.setOnItemClickListener(new OnItemClickListener() {

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

                                HashMap<String, String> o= (HashMap<String, String>) list.getItemAtPosition(position);                  

                                Toast.makeText(CustomizedListView.this, "ID '" + o.get("title") + "' was clicked.", Toast.LENGTH_SHORT).show(); 



            }
        });     
    }   
}

以下代码完美运行:

public class Main extends ListActivity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.listplaceholder);

        ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();


        JSONObject json = JSONfunctions.getJSONfromURL("http://api.geonames.org/earthquakesJSON?north=44.1&south=-9.9&east=-22.4&west=55.2&username=demo");

        try{

            JSONArray  earthquakes = json.getJSONArray("earthquakes");

            for(int i=0;i<earthquakes.length();i++){                        
                HashMap<String, String> map = new HashMap<String, String>();    
                JSONObject e = earthquakes.getJSONObject(i);

                map.put("id",  String.valueOf(i));
                map.put("name", "Earthquake name:" + e.getString("eqid"));
                map.put("magnitude", "Magnitude: " +  e.getString("magnitude"));
                mylist.add(map);            
            }       
        }catch(JSONException e)        {
             Log.e("log_tag", "Error parsing data "+e.toString());
        }

        ListAdapter adapter = new SimpleAdapter(this, mylist , R.layout.main, 
                        new String[] { "name", "magnitude" }, 
                        new int[] { R.id.item_title, R.id.item_subtitle });

        setListAdapter(adapter);

        final ListView lv = getListView();
        lv.setTextFilterEnabled(true);  
        lv.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {              
                @SuppressWarnings("unchecked")
                HashMap<String, String> o = (HashMap<String, String>) lv.getItemAtPosition(position);                   
                Toast.makeText(Main.this, "ID '" + o.get("id") + "' was clicked.", Toast.LENGTH_SHORT).show(); 

            }
        });
    }
}

LogCAT:

threadid=1: thread exiting with uncaught exception (group=0x40ab0228)
 FATAL EXCEPTION: main
 java.lang.ClassCastException: java.lang.Integer cannot be cast to java.util.HashMap
    at com.example.androidhive.CustomizedListView$1.onItemClick(CustomizedListView.java:94)
    at android.widget.AdapterView.performItemClick(AdapterView.java:292)
    at android.widget.AbsListView.performItemClick(AbsListView.java:1077)
    at android.widget.AbsListView$PerformClick.run(AbsListView.java:2533)
    at android.widget.AbsListView$1.run(AbsListView.java:3198)
    at android.os.Handler.handleCallback(Handler.java:605)
    at android.os.Handler.dispatchMessage(Handler.java:92)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:4945)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
    at dalvik.system.NativeStart.main(Native Method)

LazyAdapter.java

LazyAdapter.java

public class LazyAdapter extends BaseAdapter {

    private Activity activity;
    private ArrayList<HashMap<String, String>> data=new ArrayList<HashMap<String, String>>();
    private static LayoutInflater inflater=null;
    public ImageLoader imageLoader; 


   public static HashMap<String, String> song;

    public LazyAdapter(Activity a, ArrayList<HashMap<String, String>> d) {
        activity = a;
        data=d;
        inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        imageLoader=new ImageLoader(activity.getApplicationContext());
    }

    public int getCount() {
        return data.size();
    }

    public Object getItem(int position) {
        return position;
    }

    public long getItemId(int position) {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        View vi=convertView;
        if(convertView==null)
            vi = inflater.inflate(R.layout.list_row, null);

        TextView title = (TextView)vi.findViewById(R.id.title); // title
        TextView artist = (TextView)vi.findViewById(R.id.artist); // artist name
        TextView duration = (TextView)vi.findViewById(R.id.duration); // duration
        ImageView thumb_image=(ImageView)vi.findViewById(R.id.list_image); // thumb image

         song = new HashMap<String, String>();
        song = data.get(position);

        // Setting all values in listview
        title.setText(song.get(CustomizedListView.KEY_TITLE));
        artist.setText(song.get(CustomizedListView.KEY_ARTIST));
        duration.setText(song.get(CustomizedListView.KEY_DURATION));
        imageLoader.DisplayImage(song.get(CustomizedListView.KEY_THUMB_URL), thumb_image);
        return vi;
    }
}

推荐答案

在您的自定义适配器中，您返回的是位置而不是 Item

In you custom Adapter you are returning position instead of Item

public Object getItem(int position) {
            return position;
        }

试试这个

 public Object getItem(int position) {
                return data.get(position);
            }

这将解决您的问题

这篇关于hashmap 在 simpleadapter 中工作，但在自定义数组适配器中不工作的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！