Question

I have an android application which request for images to server and should display that request image in ImageView. Images are stored in image folder and its path is stored in MySQL database. I am using php for server side scripting. Android app request for particular image to image.php file which brings the path of the folder in which that requested image is present from database and returns it in json format. Now my question is:

Is that path alone enough for displaying image in android app? Or should the app download that image first in order to display it?
I saw somewhere in SO that you can encode image to string and return that string to android app and decode that string back to image? Is it an efficient way?

It is more of a general question so any thing would be appreciated.

Answer 1

Yeah, you have to download the image in order to display it, but you don't have to store it forever, you can decode the ByteArray using BitmapFactory to get the Bitmap of your image. Or use a lib like Picasso to "cache" your image, like it was suggested on another answer.

This question discusses many methods on how to download images on Android using some libs. Or you could try a native approach, like this:

public class LoginActivity extends Activity implements OnClickListener {

   protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.login);

   this.findViewById(R.id.userinfo_submit).setOnClickListener(this);
   // Verify Code
   LinearLayout view = (LinearLayout) findViewById(R.id.txt_verify_code);
   view.addView(new VerifyCodeView(this));

   // show The Image
   new DownloadImageTask((ImageView) findViewById(R.id.imageView1))
   .execute(“http://java.sogeti.nl/JavaBlog/wp-content/uploads/2009/04/android_icon_256.png”);
   }

  public void onClick(View v) {
    startActivity(new Intent(this, IndexActivity.class));
    finish();
  }

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

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

    protected Bitmap doInBackground(String… urls) {
      String urldisplay = urls[0];
      Bitmap mIcon11 = null;
      try {
        InputStream in = new java.net.URL(urldisplay).openStream();
        mIcon11 = BitmapFactory.decodeStream(in);
      } catch (Exception e) {
        Log.e(“Error”, e.getMessage());
        e.printStackTrace();
      }
      return mIcon11;
    }

    protected void onPostExecute(Bitmap result) {
      bmImage.setImageBitmap(result);
    }
  }
}

This code was taken from here.

You can encode your image as a Base64 String on your server and decode it on your Android later.

To decode it try the following:

byte[] data = Base64.decode(base64Image, Base64.DEFAULT);
Bitmap bm;
BitmapFactory.Options opt = new BitmapFactory.Options();
opt.inMutable = true;
bm = BitmapFactory.decodeByteArray(data, 0, data.length, opt);

// Now do whatever you want with the Bitmap.

You can see the docs for the Bitmap class here.

But honestly, you're just adding another step to the process and wasting processor cycles with that. I guess it's more efficient to just download the image as it is.

For more info on the Base64 class, please refer to the docs.

Answer 2

Try Picasso. It's easy and simple

    Picasso.with(context)
       .load("http://i.imgur.com/DvpvklR.png")//Your image link url
       .into(imageView);//Your imageView

Full docs can be found here.

Answer 3

If you have a URL for the image, I would recommend using Glide or Picasso.

GLIDE:

https://github.com/bumptech/glide

Glide.with(myFragment)
        .load(url)
        .centerCrop()
        .placeholder(R.drawable.loading_spinner)
        .into(myImageView);

PICASSO:

http://square.github.io/picasso/

Picasso.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView);

If you are using Android Studio, either of these libraries can easily be added to your Android project by adding them as dependencies in your app's Gradle file.

Add this to dependencies in your Gradle file for Glide:

compile 'com.github.bumptech.glide:glide:3.6.0'

Add this to dependencies in your Gradle file for Picasso:

compile 'com.squareup.picasso:picasso:2.5.2'

Receiving image from server in android

3 个答案: