Android存储路径在设备上不一样？

Question

Hej community! I want to read mp3 files from the storage of the device using File = Environment.getexternaldirectory() or something like this. I get a null pointer exc. when I try to get Files from there. In my phone I looked up the path of a file in a file explorer. It said storage\\emulated\\0 same as in my code. So, what is wrong? Thanks in advance.

Answer 1

Use this method to retrieve a List of files.

public List<File> getMP3Files(String directory) {
    List<File> files = new ArrayList<File>();
    File folder = new File(directory);
    for (File file : folder.listFiles()) {
        if (file.isFile()) {
            if (file.getName().endsWith(".mp3") || file.getName().endsWith(".MP3")) {
                files.add(file);
            }
        }
    }
    return files;
}

for example if you have your .mp3 files located in: "/storage/emulated/0", you only need.

String directoryPath=Environment.getExternalStorageDirectory().getPath(); // path /storage/emulated/0/                  
List<File> list = getMP3Files(directoryPath); 

If you have your .mp3 in other location, for example i have my .mp3 files in: "/storage/emulated/0/Music/Overkill"

 String mp3Directory = "/Music/Overkill";
 String directoryPath=Environment.getExternalStorageDirectory().getPath() + mp3Directory; 
 List<File> list = getMP3Files(directoryPath); 

//print in LogCat the list of .mp3:
for (File file : list) {     
        Log.i("MP3 File name", file.getName());
    }