How to rename file in android?

Question

I can apply a prefix dot (".") to all the files having .gif extension successfully. For instance, rename "my_file.gif" to ".my_file.gif"). However, I want to remove this prefix dot again using code (AKA reverse it). I have tried, but it won't work. (simply does not remove the dot) below is my code and my approach -

this is the code for adding a dot prefix(which works fine)-

    // getting SDcard root path
    File dir = new File(Environment.getExternalStorageDirectory()
            .getAbsolutePath());
    walkdir(dir);
}
//detect files having these extensions and rename them
public static final String[] TARGET_EXTENSIONS = { "gif"};
public void walkdir(File dir) { 
    File listFile[] = dir.listFiles();
    if (listFile != null) {
        for (int i = 0; i < listFile.length; i++) {
            if (listFile[i].isDirectory()) {
                walkdir(listFile[i]);
            } else {
                String fPath = listFile[i].getPath();
                for (String ext : TARGET_EXTENSIONS) {
                    if (fPath.endsWith(ext)) {
                        putDotBeforeFileName(listFile[i]);
                    }
                }
            }
        }
    }
}

private String putDotBeforeFileName(File file) {
    String fileName = file.getName();
    String fullPath = file.getAbsolutePath();
    int indexOfFileNameStart = fullPath.lastIndexOf(fileName);
    StringBuilder sb = new StringBuilder(fullPath);
    sb.insert(indexOfFileNameStart, ".");
    String myRequiredFileName = sb.toString();
    file.renameTo(new File(myRequiredFileName));
    return myRequiredFileName;
  }
}

and this is my approach for removing the dot prefix which doesn't work (no force closes)-

private String putDotBeforeFileName(File file) {
    String fileName = file.getName();
    String fullPath = file.getAbsolutePath();
    int indexOfDot = fullPath.indexOf(".");
    String myRequiredFileName = "";
    if (indexOfDot == 0 && fileName.length() > 1) {
        myRequiredFileName = file.getParent() + "/" + fileName.substring(1);
    }
    try {
        Runtime.getRuntime().exec(
                "mv " + file.getAbsolutePath() + " " + myRequiredFileName);
    } catch (IOException e) {
        e.printStackTrace();
    }
    return myRequiredFileName;
}

no sir , i want to convert ".my_file.jpg" to "myfile.jpg" (remove prefix not the extension) — patrecia, Mar 01 '16 at 09:45

Darish · Answer 1 · 2016-03-01T10:01:22.827

1

Try this code

private String removeDotBeforeFileName(File file) {
        String fileName = file.getName();
        String fullPath = file.getAbsolutePath();
        String myRequiredFileName = "";
        if (fileName.length() > 1 && fullPath.charAt(0)=='.') {
            myRequiredFileName = file.getParent() + "/" + fileName.substring(1);
           file.renameTo(new File(myRequiredFileName));
        }

        return myRequiredFileName;
    }

edited Mar 01 '16 at 10:01

answered Mar 01 '16 at 09:49

Darish

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If you want any additions, let me know :) – Darish Mar 01 '16 at 09:51
hey unfortunately your code didnt remove the dot prefix, it did nothing – patrecia Mar 01 '16 at 09:55
"Cannot invoke equals(String) on the primitive type char" – patrecia Mar 01 '16 at 09:58
just wondering why are we changing the "putDotBeforeFileName" method's name – patrecia Mar 01 '16 at 10:05
method name should indicate what it does :) – Darish Mar 01 '16 at 10:06
i tried the edit and it is still not doing anything – patrecia Mar 01 '16 at 10:06
myRequiredFileName = file.getParent() + fileName.substring(1); – Darish Mar 01 '16 at 10:13

How to rename file in android?

1 Answers1