Androidのパッケージ名に使える文字

AppStoreとあわせようとしてハマったのでメモ。

基本は英字。 先頭でなければ 数字と_が使える。

https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/content/pm/PackageParser.java#1201

    private static String validateName(String name, boolean requireSeparator,
            boolean requireFilename) {
        final int N = name.length();
        boolean hasSep = false;
        boolean front = true;
        for (int i=0; i<N; i++) {
            final char c = name.charAt(i);
            if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')) {
                front = false;
                continue;
            }
            if (!front) {
                if ((c >= '0' && c <= '9') || c == '_') {
                    continue;
                }
            }
            if (c == '.') {
                hasSep = true;
                front = true;
                continue;
            }
            return "bad character '" + c + "'";
        }
        if (requireFilename && !FileUtils.isValidExtFilename(name)) {
            return "Invalid filename";
        }
        return hasSep || !requireSeparator
                ? null : "must have at least one '.' separator";
    }