如何在 Android 上将 Google Drive 与 Picasso 集成？

我正在编写一个在 Google Drive 中存储图像的应用程序，我想显示这些图像的图库（GridView）。为了提高性能（即异步），我想将其与Picasso。但是Picasso.load(String)只是一个别名load(Uri.parse(path))，而我没有Uri因为图像是这样加载的（经过简化并使用未公开的实用方法）：

public static Bitmap getBitmap(DriveId id) {
    GoogleApiClient client = ApiClientAsyncTask.createConnectedClient(App.getAppContext());
    DriveFile file = Drive.DriveApi.getFile(client, id);
    Metadata meta = sync(file.getMetadata(client));
    Contents contents = sync(file.openContents(client, DriveFile.MODE_READ_ONLY, null));
    InputStream imageStream = contents.getInputStream();
    try {
        return BitmapFactory.decodeStream(imageStream);
    } finally {
        IOTools.ignorantClose(imageStream);
        sync(file.discardContents(client, contents));
    }
}

是否有其他类似的库可能支持任意输入（字符串/对象）的集成？

当然我想使用Picasso中对缓存（网络（上述方法）、磁盘、内存）的全面支持。

当时Picasso的版本不支持我想要的所以我就去使用Glide 3 https://github.com/bumptech/glide。这是我设法整理的内容。我还没有测试它，我把它从历史中拼凑起来，因为我从我的应用程序中删除了这个支持，这是一个矫枉过正；然而，当功能仍然存在时它就可以工作。

in ConnectionCallbacks.onConnected:

Glide.get(getContext()).register(DriveId.class, InputStream.class, new DriveIdModelLoader.Factory(mClient));

in ConnectionCallbacks.onConnectionSuspended:

Glide.get(getContext()).unregister(DriveId.class, InputStream.class);

in list Adapter:

String driveString = cursor.getString(cursor.getColumnIndex("image"));
DriveId driveId = DriveId.decodeFromString(driveString);
Glide.with(this)
     .from(DriveId.class)
     .load(driveId)
     .into(imageView);

滑行胶：

import java.io.*;

import android.content.Context;
import android.net.Uri;

import com.bumptech.glide.load.data.DataFetcher;
import com.bumptech.glide.load.model.*;
import com.bumptech.glide.load.model.stream.StreamModelLoader;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.drive.DriveId;

public class DriveIdModelLoader implements StreamModelLoader<DriveId> {
    private final GoogleApiClient client;

    public DriveIdModelLoader(GoogleApiClient client) {
        this.client = client;
    }

    public DataFetcher<InputStream> getResourceFetcher(DriveId model, int width, int height) {
        return new DriveIdDataFetcher(client, model);
    }

    public static class Factory implements ModelLoaderFactory<DriveId, InputStream> {
        private final GoogleApiClient client;

        public Factory(GoogleApiClient client) {
            this.client = client;
        }

        public ModelLoader<DriveId, InputStream> build(Context context, GenericLoaderFactory factories) {
            return new DriveIdModelLoader(client);
        }

        public void teardown() {
            client.disconnect();
        }
    }
}

驱动相关的Glide逻辑：

import java.io.InputStream;

import org.slf4j.*;

import com.bumptech.glide.Priority;
import com.bumptech.glide.load.data.DataFetcher;
import com.google.android.gms.common.api.*;
import com.google.android.gms.drive.*;

public class DriveIdDataFetcher implements DataFetcher<InputStream> {
    private static final Logger LOG = LoggerFactory.getLogger(DriveIdDataFetcher.class);

    private final GoogleApiClient client;
    private final DriveId driveId;

    private boolean cancelled = false;

    private DriveFile file;
    private Contents contents;

    public DriveIdDataFetcher(GoogleApiClient client, DriveId driveId) {
        this.client = client;
        this.driveId = driveId;
    }

    public String getId() {
        return driveId.encodeToString();
    }

    public InputStream loadData(Priority priority) {
        if (cancelled) return null;
        if (client == null) {
            LOG.warn("No connected client received, giving custom error image");
            return null;
        }
        file = Drive.DriveApi.getFile(client, driveId);
        if (cancelled) return null;
        contents = sync(file.openContents(client, DriveFile.MODE_READ_ONLY, null)).getContents();
        if (cancelled) return null;
        return contents.getInputStream();
    }

    public void cancel() {
        cancelled = true;
        if (contents != null) {
            file.discardContents(client, contents);
        }
    }

    public void cleanup() {
        if (contents != null) {
            sync(file.discardContents(client, contents));
        }
    }

    private static <T extends Result> void assertSuccess(T result) {
        if (!result.getStatus().isSuccess()) {
            throw new IllegalStateException(result.getStatus().toString());
        }
    }

    private static <T extends Result> T sync(PendingResult<T> pending) {
        T result = pending.await();
        assertSuccess(result);
        return result;
    }
}