Question

应用程序从给定的URL获取图像并显示图像，并在单击下载按钮时，它表示图像已成功下载但图库中没有图像。有人能告诉我如何解决这个问题吗？

这是我的图像查看和下载活动。我还为Android Manifest添加了适当的权限。

private Button btnImageDownload;
private ProgressDialog pd;
private ImageView viewDownloadImage;
private Images imageId;
private File folderName;
private String imageName;

private Handler handler = new Handler() {
    public void handleMessage(android.os.Message msg) {
        if (msg.what == 1) {
            if (pd != null) {
                pd.dismiss();
            }
            Utils.showNetworkAlert(ImageViewAndDownload.this);
        } else if (msg.what == 2) {
            if (pd != null) {
                pd.dismiss();
            }
            Utils.displayMessage("Image downloade succesfully",
                    ImageViewAndDownload.this);
            // Media scaning
            sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://"
                    + Environment.getExternalStorageDirectory()))); 
        } else if (msg.what == 3) {
            if (pd != null) {
                pd.dismiss();
            }
            Utils.displayMessage("Image already downloaded ",
                    ImageViewAndDownload.this);
        } else if (msg.what == 4) {
            if (pd != null) {
                pd.dismiss();
            }
            displayImageFromUrl((Bitmap) msg.obj);
        }

    }
};

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.imagedisplay);

    viewDownloadImage = (ImageView) findViewById(R.id.viewImage);
    btnImageDownload = (Button) findViewById(R.id.btnImageDownload);
    imageId = new Images();
    imageName = imageId.getImageId();
    LoadImageFromWeb(Constant.IMAGE_BASE_URL + File.separator + imageName);
    btnImageDownload.setOnClickListener(this);
}

public void onClick(View v) {
    if (v == btnImageDownload) {
        pd = ProgressDialog.show(ImageViewAndDownload.this, "",
                "Downloading Image....", true, false);
        new Thread(new Runnable() {
            public void run() {
                try {

                    String imageUrl = Constant.IMAGE_BASE_URL
                            + File.separator + imageName;
                    String isDownloded = downloadImage(imageUrl, imageName);
                    if (isDownloded.equalsIgnoreCase("complete")) {
                        handler.sendEmptyMessage(2);
                    } else if (isDownloded.equalsIgnoreCase("")) {
                        handler.sendEmptyMessage(3);
                    } else {
                        handler.sendEmptyMessage(1);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                    handler.sendEmptyMessage(1);
                }
            }
        }).start();

    }
}

// set display image to Imageview
public void displayImageFromUrl(Bitmap obj) {
    viewDownloadImage.setImageBitmap(obj);
}

// image display from the webview
private void LoadImageFromWeb(final String url1) {
    pd = ProgressDialog.show(ImageViewAndDownload.this, "",
            "Loading Image....", true, false);
    new Thread(new Runnable() {
        public void run() {
            try {

                URL url = new URL(url1);
                HttpURLConnection connection = (HttpURLConnection) url
                        .openConnection();

                InputStream is = connection.getInputStream();

                Options options = new BitmapFactory.Options();
                options.inJustDecodeBounds = true;

                BitmapFactory.decodeStream(is, null, options);

                if (options.outWidth > 3000 || options.outHeight > 2000) {
                    options.inSampleSize = 4;
                } else if (options.outWidth > 2000
                        || options.outHeight > 1500) {
                    options.inSampleSize = 3;
                } else if (options.outWidth > 1000
                        || options.outHeight > 1000) {
                    options.inSampleSize = 2;
                }
                // Do the actual decoding
                options.inJustDecodeBounds = false;

                is.close();
                is = getHTTPConnectionInputStream(url1);
                Bitmap myBitmap = BitmapFactory.decodeStream(is, null,
                        options);
                is.close();

                if (myBitmap != null) {
                    Message msg = new Message();
                    msg.obj = myBitmap;
                    msg.what = 4;
                    handler.sendMessage(msg);
                } else {
                    handler.sendEmptyMessage(1);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }).start();
}

public InputStream getHTTPConnectionInputStream(String url1) {
    URL url;
    InputStream is = null;
    try {
        url = new URL(url1);
        HttpURLConnection connection = (HttpURLConnection) url
                .openConnection();
        is = connection.getInputStream();
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return is;
}

// image download code
public String downloadImage(String imageDownloadUrl, String imageName) {
    // create directory in SDCARD
    if (android.os.Environment.getExternalStorageState().equals(
            android.os.Environment.MEDIA_MOUNTED))
        folderName = new File(Constant.STORE_IN_FOLDER);
    else
        folderName = getFilesDir();

    if (!folderName.exists())
        folderName.mkdirs();

    String response = "";
    // create file name and file.
    File storeImageInSDCard = new File(folderName + File.separator
            + imageName);
    if (!(storeImageInSDCard.exists() && storeImageInSDCard.length() > 0)) {
        // start download image
        response = downloadFile(imageDownloadUrl, imageName,
                folderName.toString());
    }
    return response;
}

// start download image
public String downloadFile(final String url, final String name,
        String foldername) {

    File file;
    FileOutputStream os = null;
    Bitmap myBitmap;
    try {

        URL url1 = new URL(url.replaceAll(" ", "%20"));
        System.out.println("Image url :::" + url1);
        HttpURLConnection urlConnection = (HttpURLConnection) url1
                .openConnection();
        urlConnection.setDoOutput(false);
        urlConnection.setRequestMethod("GET");
        urlConnection.connect();

        // here create a file which define folder name and image name with
        // extension.
        file = new File(foldername, name + ".jpg");
        InputStream inputStream = urlConnection.getInputStream();
        byte[] buffer = new byte[1024];
        int bufferLength = 0;
        os = new FileOutputStream(file);
        while ((bufferLength = inputStream.read(buffer)) > 0) {
            os.write(buffer, 0, bufferLength);
        }

        os.flush();
        os.close();

        // if image size is too large we can scale image than download.
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        myBitmap = BitmapFactory
                .decodeFile(file.getAbsolutePath(), options);
        if (options.outWidth > 3000 || options.outHeight > 2000) {
            options.inSampleSize = 4;
        } else if (options.outWidth > 2000 || options.outHeight > 1500) {
            options.inSampleSize = 3;
        } else if (options.outWidth > 1000 || options.outHeight > 1000) {
            options.inSampleSize = 2;
        }
        options.inJustDecodeBounds = false;
        myBitmap = BitmapFactory
                .decodeFile(file.getAbsolutePath(), options);

        os = new FileOutputStream(file);
        myBitmap.compress(CompressFormat.JPEG, 90, os);
        os.flush();
        os.close();
        myBitmap.recycle();

        return "complete";
    } catch (SQLException e) {
        e.printStackTrace();
        return "error";
    } catch (Exception e) {
        e.printStackTrace();
        return "error";
    }

}

}

Answer 1

试试这个，保存图像后，您必须使用此

 Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
 Uri contentUri = Uri.fromFile(file);
 mediaScanIntent.setData(contentUri);
 getApplicationContext().sendBroadcast(mediaScanIntent);

您必须向系统发送广播，更改以反映在Gallery中，以便您的图像将显示在图库中，否则，您必须重新启动设备以检查下载的图像.. < / p> 希望它可以帮助你..

Answer 2

我认为您必须使用 Aquery 进行图像下载，这对于从网络下载图像非常有用。

Here the link为Aquery

应用程序说Image已成功下载，但没有图像显示在库中

2 个答案: