Question

我需要从我的数据库加载图像，我将它们存储在blob中就像android一样。每个图像都由我的服装URI表示。如何使用Glide解决问题？

我想从Glide缓存和快速加载中受益。

有没有正确的方法呢？

Answer 1

您可以通过调用Glide.get（context）.register（）方法将自定义ModelLoader类注册到Glide。在ModelLoader中，您可以通过实现 getResourceFetcher 方法告诉Glide如何从数据库加载图像资源，并返回自定义DataFetcher实例。

这是一个例子：

DBImageUri类：

int main(){
    int testArray[] = {-2,0,44,12,-45,17,934,-21,67,88,91,1,0,6};
    int n = 14;
    int foundNegatives = countNegative(testArray,n);
    if ( ! foundNegatives ) {
         cout << "No Negative Numbers";
    }

    system("PAUSE");
    //EXIT_SUCCESS;
    return 0;
}

DBDataFetcher类：

public class DBImageUri {

private String uriString;

public DBImageUri(String uriString){
    this.uriString = uriString;
}

@Override
public String toString(){
    return uriString;
}
}

DBModelLoader类：

public class DBDataFetcher implements DataFetcher<InputStream> {

private DBImageUri uri;
private int width;
private int height;

private InputStream stream;

public DBDataFetcher(DBImageUri uri, int width, int height){
    this.uri = uri;
    this.width = width;
    this.height = height;
}

@Override
public InputStream loadData(Priority priority){
    String uriString = this.uri.toString();

    stream = //**load image based on uri, and return InputStream for this image. this is where you do the actual image from database loading process**;

    return stream;
}

@Override
public String getId(){
    //width & height should be ignored if you return same image resources for any resolution (return uri.toString();)
    return uri.toString() + "_" + width + "_" + height;
}

@Override
public void cleanup(){
    if (stream != null) {
        try {
            stream.close();
        } catch (IOException e) {
            // Ignore
        }
    }
}

@Override
public void cancel(){

}
}

然后通过调用：

将ModelLoader添加到Glide注册表中

public class DBModelLoader implements ModelLoader<DBImageUri, InputStream> {

@Override
public DataFetcher<InputStream> getResourceFetcher(DBImageUri model, int width, int height){

    return new DBDataFetcher(model, width, height);
}

public static class Factory implements ModelLoaderFactory<DBImageUri, InputStream>{

    @Override
    public ModelLoader<DBImageUri, InputStream> build(Context context, GenericLoaderFactory factories){
        return new DBModelLoader();
    }

    @Override
    public void teardown(){

    }

}
}

现在您可以加载数据库映像：

Glide.get(context).register(DBImageUri.class, InputStream.class, new DBModelLoader.Factory());

Glide自定义URI方案

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