如何使用Android Glide加载图像指定重试次数? [英] How to specify the number of retries using Glide for Android for loading images?

问题描述

我正在为我的Android应用程序使用glide库.

I'm using the glide library for my Android app.

我想告诉它在放弃并显示错误的占位符图像之前，重试X次图像(可能具有指数补偿！).

I would like to tell it to retry getting the image X times ( maybe with exponential backoff! ), before giving up and showing the error placeholder image.

任何想法如何做到这一点? (我正在使用Volley集成).

Any idea how to do this? (I'm using the Volley integration btw).

推荐答案

使用您自己的ResourceDecoder.我仅加载本地文件，并处理decode()中的重试计数.如果您使用其他模型，只需更改为适当的界面即可.

Use your own ResourceDecoder. I'm loading local files only and handle the retry count in decode(). If you use another model just change to the appropriate interface.

Glide 4.0.0-SNAPSHOT的示例. 自定义ResourceDecoder:

Example for Glide 4.0.0-SNAPSHOT. The custom ResourceDecoder:

public class FileDecoder implements ResourceDecoder<File, Drawable>{
    private final Context context;
    private int retryCounter = 0;

    public FileDecoder(Context context) {
        this.context = context;
    }

    @Override
    public Resource<Drawable> decode(File source, int width, int height, Options options) throws IOException{

        source = getTheFile(); //loading the image from a zip

        final Drawable icon = Drawable.createFromPath(source.getAbsolutePath());
        if(icon == null){
            if(retryCounter < 3){
                retryCounter++;
                return decode(source, width, height, options);
            }

            return null;
        }

        return new DrawableResource<Drawable>(icon) {
            @Override public Class<Drawable> getResourceClass() {
                return Drawable.class;
            }

            @Override public int getSize() {
                if (drawable instanceof BitmapDrawable) {
                    return Util.getBitmapByteSize(((BitmapDrawable) drawable).getBitmap());
                } else {
                    return 1;
                }
            }

            @Override public void recycle() {}
        };
    }

    @Override public boolean handles(File source, Options options) throws IOException {
        return true;
    }
}

必需的自定义ModelLoader

Required custom ModelLoader

public class FileModelLoader implements ModelLoader<File, File>{

    @Nullable @Override
    public LoadData<File> buildLoadData(final File file, int width, int height, Options options){
        return new LoadData<>(new ObjectKey(file), new DataFetcher<File>() {
            @Override
            public void loadData(Priority priority, DataCallback<? super File> callback) {
                callback.onDataReady(file);
            }

            @Override public void cleanup() {

            }

            @Override public void cancel() {

            }

            @Override public Class<File> getDataClass() {
                return File.class;
            }

            @Override public DataSource getDataSource() {
                return DataSource.LOCAL;
            }
        });
    }

    @Override public boolean handles(File file){
        return true;
    }
}

注册您的自定义模块

public class CustomGlideModule implements GlideModule{

    @Override public void applyOptions(Context context, GlideBuilder builder){
        builder.setDefaultRequestOptions(RequestOptions.formatOf(DecodeFormat.PREFER_RGB_565)); //less memory consumption but less quality
    }

    @Override public void registerComponents(Context context, Registry registry){
        registry.append(File.class, File.class, new ModelLoaderFactory<File, File>(){
            @Override public ModelLoader<File, File> build(MultiModelLoaderFactory multiFactory){
                return new FileModelLoader();
            }

            @Override public void teardown(){

            }
        }).append(File.class, Drawable.class, new FileDecoder(context));
    }
}

添加到mainfest

Add to mainfest

<application>
    ...

    <meta-data
    android:name="com.fileloader.glide.CustomGlideModule"
    android:value="GlideModule" />

</application>

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