Question

我正试图在listview上的“OnClick”事件中找回一个对象（在我的情况下是一个Wallpaper对象），我试图通过两种方式来管理它，但每次我得到：“{{ 1}}”。

第一个解决方案：InvocationTargetException.class

第二个解决方案：Wallpaper obj = (Wallpaper) listV.getItemAtPosition(position);

我在MainActivity中的代码：

Wallpaper obj = (Wallpaper ) adapter.getItem(position);

在我的其他一个项目中，我使用了第一个解决方案并且运行良好。我没有看到任何差异..

编辑：

我的任务中设置的适配器已完成：

    ListView listV = null;
    LazyAdapter adapter;

    public final static String EXTRA_MESSAGE = "com.project.samplelist.MESSAGE";
    public String message = null;
    public Wallpaper wallpaperMessage = null;

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

        final JsonDownloaderTask task = new JsonDownloaderTask(this);
        task.execute(url); //download json data and set to wallpaper object and set Lazyadapter

        listV = (ListView) findViewById(R.id.list);
        /*adapter = new LazyAdapter(this, wallpList);        
        listV.setAdapter(adapter);*/

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

                Wallpaper obj = (Wallpaper) listV.getItemAtPosition(position); // get wallpaper object on click
                message = obj.getFullscreen(); // create message
                wallpaperMessage = obj;

                Intent wallpaperFullScreenActivity = new Intent(MainActivity.this, FullscreenActivity.class);
                wallpaperFullScreenActivity.putExtra(EXTRA_MESSAGE, message); 
                wallpaperFullScreenActivity.putExtra("id", obj.getId());

                startActivity(wallpaperFullScreenActivity);             
            }
        });
    }

编辑：

我没有任何堆栈跟踪..只是我在调试模式下按F6两次在同一行：public void jsonTaskComplete(JSONArray data) { ArrayList<Wallpaper> wallpapersList = new ArrayList<Wallpaper>(); Wallpaper w = null; String id = ""; String preview = ""; String fullscreen = ""; String tags = ""; String size = ""; try { for(int indexData = 0; indexData < data.length(); indexData++) { w = new Wallpaper(); // Fetching data id = data.getJSONObject(indexData).getString("id"); preview = data.getJSONObject(indexData).getString("preview"); fullscreen = data.getJSONObject(indexData).getString("fullscreen"); tags = data.getJSONObject(indexData).getString("tags"); size = data.getJSONObject(indexData).getString("size"); // Setting data w.setId(id); w.setPreview(preview); w.setFullscreen(fullscreen); w.setSize(size); w.setTags(tags); // Adding result as a wallpaper object in the list wallpapersList.add(w); } } catch (JSONException e) { e.printStackTrace(); } listV.setAdapter(new LazyAdapter(this, wallpapersList)); }

我得到了InvocationTargetException.class（找不到源代码）和这个：

Wallpaper obj = (Wallpaper) listV.getItemAtPosition(position);

Answer 1

将此行从JsonTaskComplete移至类级别，使其成为类字段：

ArrayList<Wallpaper> wallpapersList = new ArrayList<Wallpaper>();

现在执行此操作以获取OnItemClickListener

中的壁纸

Wallpaper obj =  wallpapersList.get(position);

Listview在点击事件上获取对象

1 个答案: