从 URL 加载图像并保存在 android 中的 memory

Question

How to load image from URL and save that on memory of device in android? Dont say me use Picasso or oser laibrary. I need to: If device get internet conection I load image to ImageView from url and save it on memory of device, else I need to load one of save image to imageView. Thank`s for helps

PS Sorry me, I can make some mistakes in question because I don`t very good know English. This my class:

public class ImageManager {
    String file_path;
    Bitmap bitmap = null;
    public Bitmap donwoaledImageFromSD() {

       File image = new File(Environment.getExternalStorageDirectory().getPath(),file_path);
       BitmapFactory.Options bmOptions = new BitmapFactory.Options();
       bitmap = BitmapFactory.decodeFile(image.getAbsolutePath(),bmOptions);

        return bitmap;
    }

    private void savebitmap() {
        File file = new File("first");
        file_path = file.getAbsolutePath();
        try {
            FileOutputStream fileOutputStream = new FileOutputStream(file);
            bitmap.compress(Bitmap.CompressFormat.JPEG, 90,fileOutputStream);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void fetchImage(final String url, final ImageView iView) {
        new AsyncTask<String, Void, Bitmap>() {
            protected Bitmap doInBackground(String... iUrl) {

                try {
                    InputStream in = new URL(url).openStream();
                    bitmap = BitmapFactory.decodeStream(in);
                    savebitmap();

                } catch (Exception e) {
                    donwoaledImageFromSD();
                }
                return bitmap;
            }

            protected void onPostExecute(Bitmap result) {
                super.onPostExecute(result);
                if (iView != null) {
                    iView.setImageBitmap(result);
                }
            }
        }.execute(url);
    }
}

Answer 1

Try to use this code:

Method for loading image from imageUrl

public Bitmap getBitmapFromURL(String imageUrl) {
        try {
            URL url = new URL(imageUrl);
            HttpURLConnection connection = (HttpURLConnection) 

    url.openConnection();
                connection.setDoInput(true);
                connection.connect();
                InputStream inputStream = connection.getInputStream();
                Bitmap imageBitmap = BitmapFactory.decodeStream(inputStream);
                return imageBitmap;
            } catch (IOException e) {
                e.printStackTrace();
                return null;
            }
        }

And You should use it in a separate thread, like that:

new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Bitmap bitmap = getBitmapFromURL(<URL of your image>);
                    imageView.setImageBitmap(bitmap);

                } catch (Exception e) {

                    e.printStackTrace();
                    e.getMessage();
                }

            }
        }).start();

But using Picasso - indeed a better way.

Update:

For saving Bitmap to file on external storage (SD card) You can use method like this:

    public static void writeBitmapToSD(String aFileName, Bitmap aBitmap) {

            if (!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
                return;
            }

            File sdPath = Environment.getExternalStorageDirectory();
            File sdFile = new File(sdPath, aFileName);

            if (sdFile.exists()) {
                sdFile.delete ();
            }

            try {
                FileOutputStream out = new FileOutputStream(sdFile);
                aBitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
                out.flush();
                out.close();
            } catch (Exception e) {

            }

        }

Remember that You need

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

for it.

And for loading `Bitmap` from file on external storage You can use method like that:

public static Bitmap loadImageFromSD(String aFileName) {
        Bitmap result = null;
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            try {
                FileInputStream fis = new FileInputStream(new File(Environment.getExternalStorageDirectory(), aFileName));
                result = BitmapFactory.decodeStream(fis);
                fis.close();
            } catch (FileNotFoundException e) {
                Log.d(TAG, "loadImageFromSD: " + e.getMessage());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return result;
    }

You need

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

to do this.

Update 2

Method getBitmapFromURL() , but ImageView should be updated from UI thread, so You should call getBitmapFromURL() , for example, this way:

new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    final Bitmap bitmap = getBitmapFromURL("<your_image_URL>");

                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            imageView.setImageBitmap(bitmap);
                        }
                    });


                } catch (Exception e) {

                    e.printStackTrace();
                    e.getMessage();
                }

            }
        }).start();

Answer 2

I had this same issue and I hope this helps. First, To download Image from URL into your app, use the code below:

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;
        }

In order for the image to be displayed inside the app, use the method below in your onCreate method:

new DownloadImageTask((ImageView) -your imageview id-).execute(-your URL-);

In order for the image to be saved INTERNALLY inside the app/phone, use the code below:

@SuppressLint("WrongThread")
        protected void onPostExecute(Bitmap result) {
            if (result != null) {
                File dir = new File(peekAvailableContext().getFilesDir(), "MyImages");
                if(!dir.exists()){
                    dir.mkdir();
                }
                File destination = new File(dir, "image.jpg");

                try {
                    destination.createNewFile();
                    ByteArrayOutputStream bos = new ByteArrayOutputStream();
                    result.compress(Bitmap.CompressFormat.PNG, 0, bos);
                    byte[] bitmapdata = bos.toByteArray();

                    FileOutputStream fos = new FileOutputStream(destination);
                    fos.write(bitmapdata);
                    fos.flush();
                    fos.close();

                } catch (IOException e) {
                    e.printStackTrace();
                }
            bmImage.setImageBitmap(result);
        }

    }

To load the image from the internal storage, use the code below:

private void loadImageFromStorage(String path)
    {

  

  try {
        File f=new File(path, "image.jpg");
        Bitmap b = BitmapFactory.decodeStream(new FileInputStream(f));
        ImageView img=(ImageView)findViewById(R.id.businessCard_iv);
        img.setImageBitmap(b);
    }
    catch (FileNotFoundException e)
    {
        e.printStackTrace();
    }

}

Things to note: 1. path is the a string containing the path of the file. 2. "image.jpg" is the file name so ensure that matches with yours. 3. "MyImages" is a folder in your path which contains the actual saved image.