Android 如何从 url 保存图像？

How can I save an image from a url?

提问by Amit

I'm setting an ImageView using setImageBitmapwith an external image url. I would like to save the image so it can be used later on even if there is no internet connection. Where and how can I save it?

我正在使用setImageBitmap外部图像 url设置 ImageView 。我想保存图像，以便以后即使没有互联网连接也可以使用。我在哪里以及如何保存它？

回答by coderplus

URL imageurl = new URL("http://mysite.com/me.jpg"); 
Bitmap bitmap = BitmapFactory.decodeStream(imageurl.openConnection().getInputStream()); 

This code will help you in generating the bitmap from the image url.

此代码将帮助您从图像 url 生成位图。

This questionanswers the second part.

这个问题回答了第二部分。

回答by Sarim Sidd

You have to save it in SD card or in your package data, because on runtime you only have access to these. To do that this is a good example

您必须将其保存在 SD 卡或包数据中，因为在运行时您只能访问这些。要做到这一点，这是一个很好的例子

URL url = new URL ("file://some/path/anImage.png");
InputStream input = url.openStream();
try {
//The sdcard directory e.g. '/sdcard' can be used directly, or 
//more safely abstracted with getExternalStorageDirectory()
File storagePath = Environment.getExternalStorageDirectory();
OutputStream output = new FileOutputStream (storagePath + "/myImage.png");
try {
    byte[] buffer = new byte[aReasonableSize];
    int bytesRead = 0;
    while ((bytesRead = input.read(buffer, 0, buffer.length)) >= 0) {
        output.write(buffer, 0, bytesRead);
    }
} finally {
    output.close();
}
} finally {
input.close();
}

Source : How do I transfer an image from its URL to the SD card?

来源：如何将图像从其 URL 传输到 SD 卡？

回答by Kishan Solanki

If you are using Kotlinand Glidein your app then this is for you:

如果您在您的应用中使用Kotlin和Glide，那么这适合您：

Glide.with(this)
                .asBitmap()
                .load(imageURL)
                .into(object : SimpleTarget<Bitmap>(1920, 1080) {
                    override fun onResourceReady(bitmap: Bitmap, transition: Transition<in Bitmap>?) {
                        saveImage(bitmap)
                    }
                })

and this is that function

这就是那个功能

internal fun saveImage(image: Bitmap) {
    val savedImagePath: String

    val imageFileName = System.currentTimeMillis().toString() + ".jpg"
    val storageDir = File(Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES).toString() + "/Folder Name")
    var success = true
    if (!storageDir.exists()) {
        success = storageDir.mkdirs()
    }
    if (success) {
        val imageFile = File(storageDir, imageFileName)
        savedImagePath = imageFile.absolutePath
        try {
            val fOut = FileOutputStream(imageFile)
            image.compress(Bitmap.CompressFormat.JPEG, 100, fOut)
            fOut.close()
        } catch (e: Exception) {
            e.printStackTrace()
        }

        galleryAddPic(savedImagePath)
    }
}


private fun galleryAddPic(imagePath: String) {
    val mediaScanIntent = Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE)
    val f = File(imagePath)
    val contentUri = FileProvider.getUriForFile(applicationContext, packageName, f)
    mediaScanIntent.data = contentUri
    sendBroadcast(mediaScanIntent)
}

galleryAddPic()is used to see the image in a phone gallery.

galleryAddPic()用于查看手机图库中的图像。

Note:now if you face file uri exception then thiscan help you.

注意：现在如果您遇到文件 uri 异常，那么这可以帮助您。

回答by MAC

you can save image in sdcard and you can use that image in future without internet.

您可以将图像保存在 sdcard 中，以后可以在没有互联网的情况下使用该图像。

see this tutorialwill show how to store image and again read it.

请参阅本教程将展示如何存储图像并再次阅读它。

Hope this will help you.....!

希望能帮到你.....！

回答by Aklesh Singh

May be its will help someone like me one day

也许有一天它会帮助像我这样的人

 new SaveImage().execute(mViewPager.getCurrentItem());//calling function

private void saveImage(int currentItem) {
    String stringUrl = Site.BASE_URL + "socialengine/" + allImages.get(currentItem).getMaster();
    Utils.debugger(TAG, stringUrl);

    HttpURLConnection urlConnection = null;
    try {
        URL url = new URL(stringUrl);
        urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setRequestMethod("GET");
        urlConnection.setDoOutput(true);
        urlConnection.connect();
        File sdCardRoot = Environment.getExternalStorageDirectory().getAbsoluteFile();

        String fileName = stringUrl.substring(stringUrl.lastIndexOf('/') + 1, stringUrl.length());
        String fileNameWithoutExtn = fileName.substring(0, fileName.lastIndexOf('.'));

        File imgFile = new File(sdCardRoot, "IMG" + System.currentTimeMillis() / 100 + fileName);
        if (!sdCardRoot.exists()) {
            imgFile.createNewFile();
        }

        InputStream inputStream = urlConnection.getInputStream();
        int totalSize = urlConnection.getContentLength();
        FileOutputStream outPut = new FileOutputStream(imgFile);

        int downloadedSize = 0;
        byte[] buffer = new byte[2024];
        int bufferLength = 0;
        while ((bufferLength = inputStream.read(buffer)) > 0) {
            outPut.write(buffer, 0, bufferLength);
            downloadedSize += bufferLength;
            Utils.debugger("Progress:", "downloadedSize:" + Math.abs(downloadedSize*100/totalSize));
        }
        outPut.close();
        //if (downloadedSize == totalSize);
            //Toast.makeText(context, "Downloaded" + imgFile.getPath(), Toast.LENGTH_LONG).show();
    } catch (IOException e) {
        e.printStackTrace();
    }

}

 private class SaveImage extends AsyncTask<Integer, Void, String> {

    @Override
    protected String doInBackground(Integer... strings) {
        saveImage(strings[0]);
        return "saved";
    }

    @Override
    protected void onPostExecute(String s) {
        Toast.makeText(context, "" + s, Toast.LENGTH_SHORT).show();
    }
}