java - 具有 GridView 的 fragment 可显示 url 路径中的图像

Question

我正在尝试制作一个显示图像的 GridView ，因此它显示 GridView 但没有图像，如果单击它， GridView 会弹出链接。我不知道为什么我的图像在 gridview 上丢失了......

这是我的 fragment 类

public class FragmentD extends Fragment {
    public FragmentD(){}
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_d, container, false);

    try {
        EditText main_searchField = (EditText) rootView.findViewById(R.id.editText_search_d);
        String main_search = main_searchField.getText().toString();

        Spinner main_categoryField = (Spinner) rootView.findViewById(R.id.spinner_d);
        String category = main_categoryField.getSelectedItem().toString();

        GridView main_gridviewField = (GridView) rootView.findViewById(R.id.gridView_main);
        main_gridviewField.setAdapter(new MyGridViewAdapter(getActivity()));


        main_gridviewField.setOnItemClickListener(new AdapterView.OnItemClickListener()  {

            public void onItemClick(AdapterView<?> arg0, View view, int position,long arg3) {
                Toast.makeText(getActivity(), MyGridViewConfig.getResim_list().
                        get(position), Toast.LENGTH_SHORT).show();

            }
        });

        if(main_gridviewField.isActivated()){
            ImageView sad_face = (ImageView)getActivity().findViewById(R.id.imageView_main_sadface);
            sad_face.setVisibility(View.INVISIBLE);
            TextView nosuchdata = (TextView)getActivity().findViewById(R.id.textView_main_nodatafound);
            nosuchdata.setVisibility(View.INVISIBLE);
        }


    } catch (Exception e){
        Toast.makeText(getActivity(), "EPIC FAIL", Toast.LENGTH_LONG).show();
    }

    //new search_mainActivity(getActivity()).execute(main_search, category);

    return rootView;
}

}

这是我的适配器

public class MyGridViewAdapter extends BaseAdapter implements ListAdapter {

private Context context;

public MyGridViewAdapter(Context context) {
    super();
    this.context = context;

    MyGridViewConfig.addImageUrls();
}


public int getCount() {
    return MyGridViewConfig.getResim_list().size();

}

public Object getItem(int position) {

    return MyGridViewConfig.getResim_list().get(position);
}


public long getItemId(int position) {

    return position;
}

public View getView(int position, View convertView, ViewGroup parent) {
    ImageView imageView;
    if(convertView==null)
    {
        imageView=new ImageView(context);
        imageView.setLayoutParams(new GridView.LayoutParams(100,100));
        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setPadding(5,5,5,5);
    }else{
        imageView=(ImageView)convertView;

    }

    imageView.setImageDrawable(LoadImageFromURL(MyGridViewConfig.
            getResim_list().get(position)));
    return imageView;
}

private Drawable LoadImageFromURL(String url)

{
    try
    {
        InputStream is = (InputStream) new URL(url).getContent();
        Drawable d = Drawable.createFromStream(is, "src");
        return d;
    }catch (Exception e) {
        System.out.println(e);

        return null;
    }
}
}

这是我的配置java

public class MyGridViewConfig {

private static ArrayList<String> resim_list=new ArrayList<String>();

public static ArrayList<String> getResim_list() {
    return resim_list;

}

public static void setResim_list(ArrayList<String> resim_list) {
    MyGridViewConfig.resim_list = resim_list;
}
public static void addImageUrls(){
    //  Here you have to specify your image url path

    resim_list.add("http://fc08.deviantart.net/fs71/f/2010/319/d/6/neko_chibi__s_by_alykun17-d32y2v5.jpg");
    resim_list.add("http://fc08.deviantart.net/fs71/f/2010/319/d/6/neko_chibi__s_by_alykun17-d32y2v5.jpg");
    resim_list.add("http://fc08.deviantart.net/fs71/f/2010/319/d/6/neko_chibi__s_by_alykun17-d32y2v5.jpg");
    resim_list.add("http://fc08.deviantart.net/fs71/f/2010/319/d/6/neko_chibi__s_by_alykun17-d32y2v5.jpg");
    resim_list.add("http://fc08.deviantart.net/fs71/f/2010/319/d/6/neko_chibi__s_by_alykun17-d32y2v5.jpg");
    resim_list.add("http://fc08.deviantart.net/fs71/f/2010/319/d/6/neko_chibi__s_by_alykun17-d32y2v5.jpg");

}
}

Answer 1

您无法在主 UI 线程上下载图像，因此请在 AsyncTask 中执行此操作。创建这个类:

class LoadImageTask extends AsyncTask<String, Void, Drawable > {
    public LoadImageTask(ImageView iv)
    {
        imageView = iv;
    }
    ImageView imageView;
    protected Drawable doInBackground(String... urls) {
        try {
            URLConnection connection = new URL(urls[0]).openConnection();
            connection.connect();
            InputStream is = (InputStream) connection.getContent();
            Drawable d = Drawable.createFromStream(is, "src");
            return d;
        } catch (Exception e) {
            // e.printStackTrace();
            return null;
        }
    }

    protected void onPostExecute(Drawable drawable) {
        if(drawable != null)
            imageView.setImageDrawable(drawable);
    }
}

然后更改 getView() 函数以使用 AsyncTask 而不是 LoadImageFromURL:

// imageView.setImageDrawable(LoadImageFromURL(MyGridViewConfig.
//        getResim_list().get(position)));
new LoadImageTask(imageView).execute(MyGridViewConfig.getResim_list().get(position));