如何在Android上将Google云端硬盘与Picasso集成？

Question

I'm writing an app which stores images in Google Drive and I'd like to display a gallery of those ( GridView ). To be more performant (ie async) I'd like to integrate this with Picasso . But the Picasso.load(String) is just an alias to load(Uri.parse(path)) , and I don't have a Uri because the images are loaded like this (simplified and with undisclosed utility methods):

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));
    }
}

Is there any other similar library maybe supporting integration of arbitrary inputs (String/Object)?

Of course I'd like to use the full support of caching (network (the above method), disk, memory) in Picasso.

Answer 1

The version of Picasso at the time didn't support what I wanted so I went to use Glide 3 . Here's what I managed to put together. I didn't test it yet, I pieced it together from history, because I removed this support from my app, it was an overkill; however it was working when the functionality was still present.

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);

Glide glue:

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();
        }
    }
}

Drive related Glide logic:

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;
    }
}

Answer 2

You can download an image from Google Drive in this way:

    //this is the original Google Drive link to the image
    String s="https://drive.google.com/file/d/0B9nFwumYtUw9Q05WNlhlM2lqNzQ/view?usp=sharing";

    //you have to get the part of the link 0B9nFwumYtUw9Q05WNlhlM2lqNzQ
    String[] p=s.split("/");
    //Create the new image link
    String imageLink="https://drive.google.com/uc?export=download&id="+p[5];
    ImageView imageView = (ImageView) findViewById(R.id.imageView);
    Picasso.with(YourActivity.this).load(imageLink).into(imageView);

that is all