how to always save image with new name and delete

问题:

i am working on a wallpaper app in which i am saving a image with same name and sending it to gallery intent.

because of saving every image with same name i am having problem of getting same image every time in gallery intent.

what happening is new image is replacing but i am getting older image in gallery intent. new image replace older image but still gallery intent shows older image instead of new image

so i want to save image with new name every time but also delete older saved image.

Note: always save image as image++ but also delete previous image too.

my code:

public void setAsWallpaper(Bitmap bitmap) {

        String dirname2 = "/Wallpaper/";

        File myDir2 = new File(Environment.getExternalStorageDirectory()
                .getPath() + dirname2);

        myDir2.mkdirs();

        String fname2 = "image" + ".jpg";
        File file2 = new File(myDir2, fname2);

        if (file2.exists())
            file2.delete();
        try {
            FileOutputStream out = new FileOutputStream(file2);
            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);
            out.flush();
            out.close();
            success = true;

        } catch (Exception e) {
            Toast.makeText(_context, "failed", Toast.LENGTH_SHORT).show();
        }

        if (success) {

            Intent intent = new Intent();
             intent.setAction(Intent.ACTION_ATTACH_DATA);
             intent.setDataAndType(Uri.parse("file://"
             + "/sdcard/Wallpaper/image.jpg"), "image/*");
             intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
             _context.startActivity(intent);

        } else {

            Toast.makeText(_context, "failed", Toast.LENGTH_SHORT).show();

        }

    }

回答1:

If you don't have an original name for the image that you can send to your method as parameter. Then, the following method to generate random file name:

public String random() {
    Random generator = new Random();
    StringBuilder randomStringBuilder = new StringBuilder();
    int randomLength = generator.nextInt(MAX_LENGTH);
    char tempChar;
    for (int i = 0; i < randomLength; i++){
        tempChar = (char) (generator.nextInt(96) + 32);
        randomStringBuilder.append(tempChar);
    }
    return randomStringBuilder.toString();
}

I usually loops throw all files in my folder and delete all images there(which is always one image). then save the new one with the random name as follow:

public void setAsWallpaper(Bitmap bitmap) {

    String dirname2 = "/Wallpaper/";

    File myDir2 = new File(Environment.getExternalStorageDirectory()
            .getPath() + dirname2);
    // delete folder and all files in it. then re-create it.
    if(myDir2.exists()) {
        String[] myFiles = myDir2.list();  
         for (int i=0; i<myFiles.length; i++) {  
             File myFile = new File(myDir2, myFiles[i]);   
             myFile.delete();  
         }
         myDir2.delete();
    }
    myDir2.mkdirs();

    String fname2 = random() + ".jpg";
    File file2 = new File(myDir2, fname2);

    if (file2.exists())
        file2.delete();
    try {
        FileOutputStream out = new FileOutputStream(file2);
        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);
        out.flush();
        out.close();
        success = true;

    } catch (Exception e) {
        Toast.makeText(_context, "failed", Toast.LENGTH_SHORT).show();
    }

    if (success) {

        Intent intent = new Intent();
         intent.setAction(Intent.ACTION_ATTACH_DATA);
         intent.setDataAndType(Uri.parse("file://"
         + "/sdcard/Wallpaper/" + fname2), "image/*");
         intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
         _context.startActivity(intent);

    } else {

        Toast.makeText(_context, "failed", Toast.LENGTH_SHORT).show();

    }

}