Android: How to check if file is image?

android image listview imagemagick

28,587

Solution 1

Try this code.

public class ImageFileFilter implements FileFilter {
   
    private final String[] okFileExtensions = new String[] {
        "jpg",
        "png",
        "gif",
        "jpeg"
    };


    public boolean accept(File file) {
        for (String extension: okFileExtensions) {
            if (file.getName().toLowerCase().endsWith(extension)) {
                return true;
            }
        }
        return false;
    }

}

It'll work fine.

Use this like new ImageFileFilter(pass file name);

Solution 2

I think if you want to check whether a file is an image, you need to read it. An image file may not obey the file extension rules. You can try to parse the file by BitmapFactory as following:

BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
Bitmap bitmap = BitmapFactory.decodeFile(path, options);
if (options.outWidth != -1 && options.outHeight != -1) {
    // This is an image file.
}
else {
    // This is not an image file.
}

28,587

Marco Seiz

Android (Newbie) Developer

Updated on October 06, 2020

Comments

Marco Seiz over 3 years

Possible Duplicate:
Know if a file is a image in Java/Android

How can I check a file if it is an image? like following:

if(file.isImage)....

If it's not possible with standard libraries, how can I do it with the MagickImage lib?

Thanks in advance!
- Praful Bhatnagar over 11 years
  
  may be you can check with the file extension..
- My Head Hurts over 11 years
  
  Possible duplicate stackoverflow.com/q/9244710/681807
- Marco Seiz over 11 years
  
  I think it's not the right way to check with file extension. Because I would have to create a function that checks EVERY image file extensions like bmp, jpg, jpeg, png, gif, tif, etc...
IAmGroot over 11 years

But you would need a try catch right?..
zsxwing over 11 years

You can just check the return value of BitmapFactory.decodeFile(path, options);
zsxwing over 11 years

options.inJustDecodeBounds = true decrease the parsing time cost since decodeFile will parse only the width and height of the image.
Zala Janaksinh over 11 years

@zsxwing if are get system file and witch have no permission to decode then get the null pointer excepetion u cant read this file and create bitmap.and another thing is when u check the multiple file every time to decode and check its increase to generate the outofMemory problem.Just think and then reply.
Marco Seiz over 11 years

hmm it says false to every image file...
Marco Seiz over 11 years

That worked... Now I have to search every image extension...
Zala Janaksinh over 11 years

@MarcoSeiz then flag my comment direct the right way to some one.
Baz almost 11 years

@zsxwing decodeFile(String, Options) will always return null if you set inJustDecodeBounds = true. Use this check to see if it was decoded successfully: if (options.outWidth != -1 && options.outHeight != -1)
Baz almost 11 years

@ZalaJanaksinh This would return true for any file that has an "image file extension", e.g. if I rename test.mp3 to test.jpg, your method would return true.
Allen Vork about 8 years

it's not the right way. Because not all the path includes the image type is a image
Zala Janaksinh about 8 years

@AllenVork then suggest what is the right way? && what is the drawback of use of that ?
Allen Vork about 8 years

try the solution below
Allen Vork almost 8 years

This is a right way to check whether a file is image.But it's a waste of time. I want another way to check a file effectively.
zsxwing almost 8 years

If you can make sure the file extensions are set correctly, checking the file extension name is the most effective way AFAIK.
Reaz Murshed over 7 years

zsxwing's answer works perfectly.
Farid over 3 years

"BitmapFactory.decodeFile()" great way to kill your app if check includes loads of files