Get Image from Urls with AsyncTask

Question

I am sure this is not a new question. Unfortunately, after fighting for this activity over 20 hours, I'm still cannot find out the solution. Could you please give me a helping hand. I will be very appreciate.

Hey is my question. I would like to show Image from different urls to a girdView layout. However, my code didn't work so the screen show nothing. Could you guy please help me to solve this?

Below is my MainActivity Class

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    String [] imgUrlList = {
            "http://image.tmdb.org/t/p/w500/cGOPbv9wA5gEejkUN892JrveARt.jpg",
            "http://image.tmdb.org/t/p/w500/6FxOPJ9Ysilpq0IgkrMJ7PubFhq.jpg",
            "http://image.tmdb.org/t/p/w500/z09QAf8WbZncbitewNk6lKYMZsh.jpg",
            "http://image.tmdb.org/t/p/w500/kqjL17yufvn9OVLyXYpvtyrFfak.jpg"
    };


    mMovieAdapter = new MyAdapter(this, imgUrlList);
    GridView gridview = (GridView) findViewById(R.id.gridView);
    gridview.setAdapter(mMovieAdapter);

}

public class MyAdapter extends ArrayAdapter<String>{
    private final Activity context;
    private final String[] imgUrlList;

    public MyAdapter (Activity context, String[] imgUrlList){
        super(context, R.layout.image_item);
        this.context = context;
        this.imgUrlList = imgUrlList;
    }

    public View getView (int position, View view, ViewGroup parent){
        LayoutInflater inflater = context.getLayoutInflater();
        View rootView = inflater.inflate(R.layout.image_item, null, true);

        new DownloadImageTask((ImageView) rootView.findViewById(R.id.imageItem)).execute(imgUrlList[position]);
        ImageView imageView = (ImageView) rootView.findViewById(R.id.imageItem);
        imageView.setImageURI(Uri.parse(imgUrlList[position]));

        return rootView;
    }
}

private class DownloadImageTask extends AsyncTask <String, Void, Bitmap>{

    ImageView poster;

    public DownloadImageTask(ImageView poster) {
        this.poster = poster;
    }

    protected Bitmap doInBackground(String... urls){
        String imageUrls = urls[0];
        Bitmap moviePoster = null;
        try {
            InputStream in = new java.net.URL(imageUrls).openStream();
            moviePoster = BitmapFactory.decodeStream(in);
        } catch (Exception e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return moviePoster;
    }

    @Override
    protected void onPostExecute(Bitmap result) {
        poster.setImageBitmap(result);
    }
}

Below is my xml (activity_main) file

<GridView
    android:id="@+id/gridView"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:columnWidth="185dp"
    android:numColumns="auto_fit"/>

I also have a imageView file call image_item

You should concider using libs like Glide/picasso/UIL, it will do a better work at loading the images — An-droid, Jul 13 '16 at 09:27
do not reinvent the wheel. use Picasso or a library of the similar sort — hello_world, Jul 13 '16 at 09:28
Use Glide. Easy to use and load images: here is the link : https://github.com/bumptech/glide — M.Waqas Pervez, Jul 13 '16 at 09:29
`ImageView poster;`. You download an image. And put it as bitmap in this imageview. After that you throw the imageview away. You should put that bitmap on the right position in your gridview instead. — greenapps, Jul 13 '16 at 09:40
`imageView.setImageURI(Uri.parse(imgUrlList[position]));`. After you started the download task you set this image uri. So why? That is double. Why does this last one not work? — greenapps, Jul 13 '16 at 09:42
For every getView you start a download task. But you should cache the images instead. You can find many examples of lazy image loading on the internet and on this site. So why continue with this faulty code? — greenapps, Jul 13 '16 at 09:46
Yup, thanks all you reply and suggest, after using the picasso !! I can finally load the image!!!! — Chow Day, Jul 14 '16 at 02:44

score 0 · Answer 1 · answered Jul 13 '16 at 14:14

0

Honestly, I don't know why. But use this constructor fix this problem:

 super(context,0,imgUrlList);

instead of

super(context, R.layout.image_item);

answered Jul 13 '16 at 14:14

Phoenix Wang

2,357
1
11
17

And frankly I don't really like your code style. Little mistakes everywhere. – Phoenix Wang Jul 13 '16 at 14:17
Thanks for your reply. I'm just start to learn coding 10day before. I know that there are lot of thing can be improve. However, I have tried to use the code you provided. But still cannot work in my phone. – Chow Day Jul 14 '16 at 00:48
Could you please tell me how to find the little mistakes? – Chow Day Jul 14 '16 at 00:53

score -2 · Answer 2 · edited Jul 13 '16 at 13:01

-2

You may use picaso library to server your purpose. https://github.com/square/picasso

You just need to initialize Picasso class and set url.

edited Jul 13 '16 at 13:01

niyasc

4,440
1
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50

answered Jul 13 '16 at 09:47

ViratBhavsar

104
4

Yes, after using Picasso and it is fine now~~thanks!! – Chow Day Jul 14 '16 at 02:43

Get Image from Urls with AsyncTask

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