Android Load Image from Url (Android 讀取網路圖片)

 

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.Point;
import android.media.ExifInterface;
import android.os.AsyncTask;
import android.os.Build;
import android.view.Display;
import java.io.InputStream;

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


    public interface ActionListener {

        public  void get_image(Bitmap result_bmp);

    }
    public  ActionListener actionListener=null;

    private  int max_width;
    private  int max_height;
    private  int  img_roataion=0;
    public  DownloadImageTask(Activity activity){
        Display display = activity.getWindowManager().getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        max_width = size.x;
        max_height = size.y;


    }


    private BitmapFactory.Options getBitmapOptions(int scale){
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inSampleSize = scale;
        options.inMutable=true;
        return options;
    }
    private  int exifToDegrees(int exifOrientation) {
        if (exifOrientation == ExifInterface.ORIENTATION_ROTATE_90) { return 90; }
        else if (exifOrientation == ExifInterface.ORIENTATION_ROTATE_180) {  return 180; }
        else if (exifOrientation == ExifInterface.ORIENTATION_ROTATE_270) {  return 270; }
        return 0;
    }
    protected Bitmap doInBackground(String... urls) {

        String urldisplay = urls[0];
        Bitmap bitmap = null;
        InputStream in;
        BitmapFactory.Options options= getBitmapOptions(1);
        options.inJustDecodeBounds=true;
        try {



        in = new java.net.URL(urldisplay).openStream();
        if(Build.VERSION.SDK_INT>=24) {
            ExifInterface exif = new ExifInterface(in);
            int rotation1 = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
            img_roataion = exifToDegrees(rotation1);
        }
        bitmap = BitmapFactory.decodeStream(in,null,options);

         if(options.outWidth>max_width && options.outHeight>max_height){
                options.inJustDecodeBounds=false;
                options.inSampleSize=2;
                in = new java.net.URL(urldisplay).openStream();
                bitmap = BitmapFactory.decodeStream(in,null,options);

            }else{
                options.inJustDecodeBounds=false;
                options.inSampleSize=1;
                in = new java.net.URL(urldisplay).openStream();
                bitmap = BitmapFactory.decodeStream(in,null,options);
            }

            if(img_roataion!=0 && bitmap!=null){
                Matrix matrix = new Matrix();
                matrix.postRotate(img_roataion);
                Bitmap rotatedBitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
                bitmap.recycle();
                bitmap= rotatedBitmap;
            }



        } catch (Exception e) {
            e.printStackTrace();
        }




        return bitmap;
    }

    protected void onPostExecute(Bitmap result) {

        if(result==null)return;

        if(actionListener!=null){
            actionListener.get_image(result);
        }

    }
}