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android – Getting list of all files of a specific type

Posted by: admin June 15, 2020 Leave a comment

Questions:

Is there a way to get a list of all files of a specific type from the sdcard? For images, we have Media.Images. Similarly, do we have any such framework below API10?

How to&Answers:

This is my FileFilter for audio files (you can change the extension list for your scenario).

package com.designfuture.music.util;

import java.io.File;
import java.io.FileFilter;
import java.io.FilenameFilter;
import java.util.ArrayList;

import com.designfuture.framework.util.LogHelper;

public class AudioFileFilter implements FileFilter {

    protected static final String TAG = "AudioFileFilter";
    /**
     * allows Directories
     */
    private final boolean allowDirectories;

    public AudioFileFilter( boolean allowDirectories) {
        this.allowDirectories = allowDirectories;
    }

    public AudioFileFilter() {
        this(true);
    }

    @Override
    public boolean accept(File f) {
        if ( f.isHidden() || !f.canRead() ) {
            return false;
        }

        if ( f.isDirectory() ) {
            return checkDirectory( f );
        }
        return checkFileExtension( f );
    }

    private boolean checkFileExtension( File f ) {
        String ext = getFileExtension(f);
        if ( ext == null) return false;
        try {
            if ( SupportedFileFormat.valueOf(ext.toUpperCase()) != null ) {
                return true;
            }
        } catch(IllegalArgumentException e) {
            //Not known enum value
            return false;    
        }
        return false; 
    }

    private boolean checkDirectory( File dir ) {
        if ( !allowDirectories ) {
            return false;
        } else {
            final ArrayList<File> subDirs = new ArrayList<File>();
            int songNumb = dir.listFiles( new FileFilter() {

                @Override
                public boolean accept(File file) {
                    if ( file.isFile() ) {
                        if ( file.getName().equals( ".nomedia" ) )
                            return false;

                        return checkFileExtension( file );
                    } else if ( file.isDirectory() ){
                        subDirs.add( file );
                        return false;
                    } else
                        return false;
                }
            } ).length;

            if ( songNumb > 0 ) {
                LogHelper.i(TAG, "checkDirectory: dir " + dir.toString() + " return true con songNumb -> " + songNumb );
                return true;
            }

            for( File subDir: subDirs ) {
                if ( checkDirectory( subDir ) ) {
                    LogHelper.i(TAG, "checkDirectory [for]: subDir " + subDir.toString() + " return true" );
                    return true;
                }
            }
            return false;
        }       
    }

    private boolean checkFileExtension( String fileName ) {
        String ext = getFileExtension(fileName);
        if ( ext == null) return false;
        try {
            if ( SupportedFileFormat.valueOf(ext.toUpperCase()) != null ) {
                return true;
            }
        } catch(IllegalArgumentException e) {
            //Not known enum value
            return false;    
        }
        return false; 
    }

    public String getFileExtension( File f ) {
        return getFileExtension( f.getName() );
    }

    public String getFileExtension( String fileName ) {
        int i = fileName.lastIndexOf('.');
        if (i > 0) {
            return fileName.substring(i+1);
        } else 
            return null;
    }

    /**
     * Files formats currently supported by Library
     */
    public enum SupportedFileFormat
    {
        _3GP("3gp"),
        MP4("mp4"),
        M4A("m4a"),
        AAC("aac"),
        TS("ts"),
        FLAC("flac"),
        MP3("mp3"),
        MID("mid"),
        XMF("xmf"),
        MXMF("mxmf"),
        RTTTL("rtttl"),
        RTX("rtx"),
        OTA("ota"),
        IMY("imy"),
        OGG("ogg"),
        MKV("mkv"),
        WAV("wav");

        private String filesuffix;

        SupportedFileFormat( String filesuffix ) {
            this.filesuffix = filesuffix;
        }

        public String getFilesuffix() {
            return filesuffix;
        }
    }

}

You have to use a FileFilter to get a filtered list of files and dir from a dir in this way:

File[] files = dir.listFiles(new AudioFileFilter());

Answer:

Try below code.

File dir = new File("path to directory");

String[] names = dir.list(
    new FilenameFilter()
    {
        public boolean accept(File dir, String name)
        {
            return name.endsWith(".your file type");
            // Example
            // return name.endsWith(".mp3");
        }
    });

Note that the returned strings are file names only, they do not contain the full path.

Answer:

Get the path of the SD card and enter all the files to an array of File:

    File[] file = Environment.getExternalStorageDirectory().listFiles();  


    for (File f : file)
    {
       if (f.isFile() && f.getpath().endswith(".something")) { ... do stuff }
    }

Answer:

I just find a more easy way to do the job.

If you’re picking something common files like images or videos, use a library.

For any other types, you can try apache’s common ios library.

First,

dependencies {
    implementation 'commons-io:commons-io:2.5'
}

Then,

val iterator = FileUtils.iterateFiles(
    Environment.getExternalStorageDirectory(),
    FileFilterUtils.suffixFileFilter("pdf"),
    TrueFileFilter.INSTANCE)
while (iterator.hasNext()) {
    val fileINeed = iterator.next()
    // do your job
}

I use picking PDFs as an example. It will handle subdictionaries automatically. So iterator contains all PDF files of my device.

Its APIs are very flexible, powerful and easy to use. You can add many filters or rules to finish your specific job XD

Answer:

I know it is too late, but just in case.
I’ll do it the kotlin way

 val accepted_extention = listOf("mp3", "3gp", "mp4")
 val ROOT_DIR = Environment.getExternalStorageDirectory().absolutePath
 val ANDROID_DIR = File("$ROOT_DIR/Android")
 val DATA_DIR = File("$ROOT_DIR/data")
 File(ROOT_DIR).walk()
               // befor entering this dir check if
               .onEnter{ !it.isHidden // it is not hidden
                         && it != ANDROID_DIR // it is not Android directory
                         && it != DATA_DIR // it is not data directory
                && !File(it, ".nomedia").exists() //there is no .nomedia file inside
               }.filter { accepted_extention.indexOf(it.extension) > -1}// it is of accepted type
               .toList()