Question

我正在尝试使用Universal Image Loader为喜欢的图片创建网格视图。目前，没有图像出现或加载。同样，我的调试也发现只调用getView = position == 0.请帮助！

下面我列出：

创建虚拟arraylist和自定义适配器的片段代码片段
片段的
使用通用图像加载器的自定义适配器和一个视图持有者，其中包含一个带有imageView的relativelayout。

gridview / viewholder项目的xml布局文件。

FavoritesFragment.java：

public class FavoritesFragment extends Fragment {

private GridView gridView;
private Button imageButton;
private FavoritesImageAdapter favoritesImageAdapter;

...

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ArrayList<String> exampleUrls = new ArrayList<String>(); //Used for testing
        exampleUrls.add("http://i.imgur.com/gOD1PVH.jpg");
        exampleUrls.add("http://i.imgur.com/HB6wZox.jpg");
        exampleUrls.add("http://i.imgur.com/gOD1PVH.jpg");
        exampleUrls.add("http://i.imgur.com/HB6wZox.jpg");
        exampleUrls.add("http://i.imgur.com/HB6wZox.jpg");
        exampleUrls.add("http://i.imgur.com/gOD1PVH.jpg");

        favoritesImageAdapter = new FavoritesImageAdapter(getActivity(), 0, exampleUrls);

        setHasOptionsMenu(true); // Allows the fragment to change the menu buttons


    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_favorites, container, false);
        gridView = (GridView) view.findViewById(R.id.gridView);

        gridView.setAdapter(favoritesImageAdapter);
        getActivity().getActionBar().setTitle("Favorites");
        return view;
    }
}

fragment_favorites.xml：

<GridView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/gridView"
    android:layout_centerVertical="true"
    android:layout_centerHorizontal="true"
    android:numColumns="3"
    android:background="@color/blue_200"
    android:layout_above="@+id/favoritesButtonLayout"/>

<LinearLayout
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:paddingBottom="10px"
    android:id="@+id/favoritesButtonLayout">

    <Space
        android:layout_weight="1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <ImageButton
        android:layout_weight="10"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/imageButton"
        android:src="@drawable/ic_action_camera"/>

    <Space
        android:layout_weight="1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <ImageButton
        android:layout_weight="10"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/videoButton"
        android:src="@drawable/ic_action_video"/>

    <Space
        android:layout_weight="1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</LinearLayout>


<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/onboardingFavoritesImageView"
    android:layout_centerVertical="true"
    android:layout_centerHorizontal="true" />

FavoritesImageAdapter.java：

公共类FavoritesImageAdapter扩展了BaseAdapter {

LayoutInflater layoutInflater;
private Context mContext;
private ArrayList<String> imageUrls;
private ImageLoader imageLoader;
DisplayImageOptions options;

public FavoritesImageAdapter(Context context, int resource, ArrayList<String> urls){
    layoutInflater = layoutInflater.from(context);
    mContext = context;
    this.imageUrls = urls;
    imageLoader = ImageLoader.getInstance();
    options = new DisplayImageOptions.Builder()
            .showImageForEmptyUri(R.drawable.ic_empty)
            .showImageOnFail(R.drawable.ic_error)
            .resetViewBeforeLoading(true)
            .cacheOnDisk(true)
            .imageScaleType(ImageScaleType.EXACTLY)
            .bitmapConfig(Bitmap.Config.RGB_565)
            .considerExifParams(true)
            .displayer(new FadeInBitmapDisplayer(300))
            .build();
}




@Override
public int getCount() {
    Log.d("howmany", ""+imageUrls.size());
    return imageUrls.size();
}

@Override
public Object getItem(int position) {
    return imageUrls.get(position);
}

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

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    final FavoritesImageViewHolder favoritesImageViewHolder;
    final String url = (String)getItem(position); //TODO If the cast works delete this TODO

    if(convertView == null){
        RelativeLayout rootView = (RelativeLayout) layoutInflater.inflate(R.layout.item_grid_favorites_image, parent, false);
        favoritesImageViewHolder = FavoritesImageViewHolder.create(rootView);
        rootView.setTag(favoritesImageViewHolder);
    }
    else{
        favoritesImageViewHolder = (FavoritesImageViewHolder) convertView.getTag();
    }

    imageLoader.displayImage((String)getItem(position), favoritesImageViewHolder.imageView, options, new SimpleImageLoadingListener() {//TODO If the cast works delete this TODO
                @Override
                public void onLoadingStarted(String imageUri, View view) {
                    //holder.progressBar.setProgress(0);
                    //holder.progressBar.setVisibility(View.VISIBLE);
                    Log.d("doesthishappen", "yes0");
                }

                @Override
                public void onLoadingFailed(String imageUri, View view,
                              FailReason failReason) {
                    //holder.progressBar.setVisibility(View.GONE);
                    Log.d("doesthishappen", "yes1");
                }

                @Override
                public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
                    //holder.progressBar.setVisibility(View.GONE);
                    Log.d("doesthishappen", "yes2");
                }
            }, new ImageLoadingProgressListener() {
                @Override
                public void onProgressUpdate(String imageUri, View view, int current,
                                             int total) {
                    //holder.progressBar.setProgress(Math.round(100.0f * current / total));
                }
            }
    );

    return favoritesImageViewHolder.rootView;

}



/**
 * ViewHolder's allow for a single object to maintain a Goal row item, so that the row item
 * doesn't have to create each individual component (textview layout etc.) each time the
 * row object is created/recreated. Allows for fast scrolling with little latency.
 */
private static class FavoritesImageViewHolder {
    public final RelativeLayout rootView;
    public final ImageView imageView;


    private FavoritesImageViewHolder(RelativeLayout rootView, ImageView imageView) {
        this.rootView = rootView;
        this.imageView = imageView;
    }

    public static FavoritesImageViewHolder create(RelativeLayout rootView){
        ImageView imageView = (ImageView)rootView.findViewById(R.id.favoritesMediaView);
        return new FavoritesImageViewHolder(rootView, imageView);
    }
}

}

item_grid_favorites_image.xml：

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/favoritesMediaView"
    android:layout_centerVertical="true"
    android:layout_centerHorizontal="true" />

我不确定为什么会这样。我知道所有6个假网址都被传递给适配器，我知道getView方法被调用了6次。我也知道Universal Image Loader永远不会到达onLoadingComplete（）回调方法，但它会调用onLoadingStarted（）6次。所有这6次使用arraylist的位置0。请帮助，我希望通过这个侧面项目在android上变得更好。另外，我为开头的代码格式错误道歉。我试图解决它，但它不起作用。

Answer 1

@eduardowarded：我观察的是你使用Holder pattern进行快速滚动。我可以建议你在FavoritesImageViewHolder中添加新属性作为int位置。在getVirew方法中，您必须分配favoritesImageViewHolder.position = position。要访问位置，您应该使用favoritesImageViewHolder.position。出现这种类型的问题是因为在滚动列表getView时会调用它并且它不同步，这会导致线程更新值。

我希望这可以帮助您解决问题。

Answer 2

希望它可以帮到你

if(convertView == null){
    RelativeLayout rootView = (RelativeLayout) layoutInflater.inflate(R.layout.item_grid_favorites_image, parent, false);
    favoritesImageViewHolder = FavoritesImageViewHolder.create(rootView);
    rootView.setTag(favoritesImageViewHolder);
//add this code to your adapter
favoritesImageViewHolder.imageView.setTag(position);
}

Answer 3

我发现了答案。我应该有一个与这个基本相同的item_grid_favorites_image.xml：https://github.com/nostra13/Android-Universal-Image-Loader/blob/master/sample/res/layout/item_grid_image.xml

如果您想了解其工作原理：

之前，我使用的是item_grid_favorites_image.xml，其相对布局具有fill_parent高度，这导致通用图像加载器永远需要加载图片。此外，这就是为什么onLoadingStarted（）被调用了6次，但是onLoadingComplete（）被调用了0次。它刚刚加载了加载时间。

TIL我是个白痴

使用通用图像加载器的GridView不显示项目＆amp;适配器getView方法只调用w / position 0

3 个答案: