Getting bitmap from URL using Picasso in AsyncTask

Question

EDIT: I have the "Method call..." error fixed. Now my main issue is actually loading in the bitmap from my URL. I'm apparently not handling it properly and I'm getting java.lang.OutOfMemoryError when I try to use the .get() method from PIcasso.

What is the best way to do this? I don't even need the whole image, just a center crop to fill the wallpaper on my device. But I can't crop it without loading it in first, which is my issue.

So I'm trying to get a bitmap from a given URL using Picasso, then paint text on top of it and set it as my wallpaper background. I'm currently attempting to do this from onPostExecute in AsyncTask. The error I'm getting is:

java.lang.IllegalStateException: Method call should not happen from the main thread.

The line of code causing the problem is:

Bitmap bitmap = Picasso.with(myContext)
                .load(url + ".jpg")
                .fit()
                .centerCrop()
                .get();

and the whole onPostExcute function:

protected void onPostExecute(String url) {

    ImageView imageView = (ImageView) rootView.findViewById(R.id.preview);
    try {
        Bitmap bitmap = Picasso.with(myContext)
                .load(url + ".jpg")
                .fit()
                .centerCrop().get();

        Canvas canvas = new Canvas(bitmap);
        Paint paint = new Paint();
        paint.setColor(Color.RED); //Text Color
        paint.setStrokeWidth(72); //Text Size
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER)); //Text Overlapping Pattern

        canvas.drawBitmap(bitmap, 0, 0, paint);
        canvas.drawText("Test...", 10, 10, paint);

        ((ImageView) rootView.findViewById(R.id.preview)).setImageBitmap(bitmap);
        WallpaperManager wallpaperManager = WallpaperManager.getInstance(myContext);
        //wallpaperManager.suggestDesiredDimensions(width, height);
        wallpaperManager.setBitmap(bitmap);

        Toast.makeText(myContext, "Wallpaper set successfully.", Toast.LENGTH_SHORT).show();
    }
    catch (Exception e) {
        android.util.Log.e(TAG, "Failed to set wallpaper", e);
    }
}

I haven't even been able to test all the canvas/paint code to see if it works. If you see anything wrong in there as well please let me know. Any and all tips are greatly appreciated. Thanks.

check if this helps http://stackoverflow.com/a/27180835/2686502 — jayeshsolanki93, Jun 02 '16 at 19:05
picasso does async for you, why are you using an `AsyncTask` on top? And what you do would have to go partially into the `doInBackgroundMethod` in case you want to combine picasso with your async task. Return the loaded and modified image and set it in `onPostExecute`. — zapl, Jun 02 '16 at 19:07

score 1 · Answer 1 · answered Jun 02 '16 at 19:16

Just putting both @jayeshsolanki93 and @zapl comments together. You are getting that error because you are calling the method get() from Picasso on the main thread. get() is a synchronous method and hence the error. You have two options:

Move the call of get() to doInBackground method of your AsyncTask and then do all your canvas operations on onPostExecute.

Take full advantage of Picasso and use the Asynchronous methods that already has and do something like this:

Picasso.with(context).load(url).into(new Target() {
    @Override
    public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
        Log.i(TAG, "The image was obtained correctly, now you can do your canvas operation!");

    }

    @Override
    public void onBitmapFailed(Drawable errorDrawable) {
        Log.e(TAG, "The image was not obtained");
    }

    @Override
    public void onPrepareLoad(Drawable placeHolderDrawable) {
        Log.(TAG, "Getting ready to get the image");
        //Here you should place a loading gif in the ImageView to
        //while image is being obtained.
    }
});

The reason I was using Picasso in AsyncTask is that I have some network code I'm using to get a URL to pass to Picasso. You guys helped me fix the main thread issue (still learning), but now I'm dealing with java.lang.OutOfMemoryError due to failing to resize the incoming image properly. I'm trying to use .resize(w,h).centerCrop().get() which isn't working. Any ideas? — blurbs78, Jun 02 '16 at 19:50

Getting bitmap from URL using Picasso in AsyncTask

1 Answers1