Android上的文件名允许哪些字符?

2. 看起来保留的文件名字符取决于安装的文件系统( http://en.wikipedia.org/wiki/Filename ).

private static final String ReservedChars = "|\\?*<\":>+[]/'";

根据 wiki

目录项中允许的字符

是

除值0-31、127(DEL)和:“*/:<>?\ |+,.;=[](小写a-z存储为a-z)。对于VFAT LFN,除NUL以外的任何Unicode

final String[] ReservedChars = {"|", "\\", "?", "*", "<", "\"", ":", ">"};

for(String c :ReservedChars){
    System.out.println(dd.indexOf(c));
    dd.indexOf(c);
}

这是正确的 输入滤波器 对于Android中的文件名:

    InputFilter filter = new InputFilter()
    {
        public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) 
        { 
            if (source.length() < 1) return null;
            char last = source.charAt(source.length() - 1);
            String reservedChars = "?:\"*|/\\<>";
            if(reservedChars.indexOf(last) > -1) return source.subSequence(0, source.length() - 1);
            return null;
        }  
    };

android.os.FileUtils

    private static boolean isValidFatFilenameChar(char c) {
        if ((0x00 <= c && c <= 0x1f)) {
            return false;
        }
        switch (c) {
            case '"':
            case '*':
            case '/':
            case ':':
            case '<':
            case '>':
            case '?':
            case '\\':
            case '|':
            case 0x7F:
                return false;
            default:
                return true;
        }
    }

    private static boolean isValidExtFilenameChar(char c) {
        switch (c) {
            case '\0':
            case '/':
                return false;
            default:
                return true;
        }
    }

Galaxy Note 8 在Android 4.4.2上。默认的“我的文件”应用程序有助于灰显无效字符,如下所示:

我将所有其他可用的特殊字符放入一个文件名中并保存了它。这在所有Android版本中可能并不一致,所以最好保守一点,用同样有意义的字符替换它们。

这显然依赖于文件系统和Android操作系统。在我的oneplus/oxygenOS上,唯一被接受的答案是

private static final String ReservedChars = "|\\?*<\":>+[]/'";

无法用于重命名文件的是/和*

在Android上 as suggested there 您可以使用输入筛选器来防止用户输入无效字符,下面是一个更好的实现:

/**
 * An input filter which can be attached to an EditText widget to filter out invalid filename characters
 */
class FileNameInputFilter: InputFilter
{
override fun filter(source: CharSequence?, start: Int, end: Int, dest: Spanned?, dstart: Int, dend: Int): CharSequence? {
    if (source.isNullOrBlank()) {
        return null
    }

    val reservedChars = "?:\"*|/\\<>\u0000"
    // Extract actual source
    val actualSource = source.subSequence(start, end)
    // Filter out unsupported characters
    val filtered = actualSource.filter { c -> reservedChars.indexOf(c) == -1 }
    // Check if something was filtered out
    return if (actualSource.length != filtered.length) {
        // Something was caught by our filter, provide visual feedback
            if (actualSource.length - filtered.length == 1) {
                // A single character was removed
                BrowserApp.instance.applicationContext.toast(R.string.invalid_character_removed)
            } else {
                // Multiple characters were removed                    
     BrowserApp.instance.applicationContext.toast(R.string.invalid_characters_removed)
                }
            // Provide filtered results then
            filtered
        } else {
            // Nothing was caught in our filter
            null
        }
    }
}