这就是我的工作…(简洁且经过测试)

    ...
    deleteDir(new File(dir_to_be_deleted));
    ...

    // delete directory and contents
    void deleteDir(File file) { 
        if (file.isDirectory())
            for (String child : file.list())
                deleteDir(new File(file, child));
        file.delete();  // delete child file or empty directory
    }

private static void deleteRecursive(File dir)
{
    //Log.d("DeleteRecursive", "DELETEPREVIOUS TOP" + dir.getPath());
    if (dir.isDirectory())
    {
        String[] children = dir.list();
        for (int i = 0; i < children.length; i++)
        {
            File temp = new File(dir, children[i]);
            deleteRecursive(temp);
        }

    }

    if (dir.delete() == false)
    {
        Log.d("DeleteRecursive", "DELETE FAIL");
    }
}

如果该目录在Java中有子目录或文件，则不能删除该目录。试试这两行简单的解决方案。这将删除目录和目录内的竞争。

File dirName = new File("directory path");
FileUtils.deleteDirectory(dirName);

在gradle文件中添加这一行并同步项目

compile 'org.apache.commons:commons-io:1.3.2'  

使用以下方法删除包含文件的整个主目录及其子目录。再次调用此方法后，调用主目录的delete()目录。

// For to Delete the directory inside list of files and inner Directory
public static boolean deleteDir(File dir) {
    if (dir.isDirectory()) {
        String[] children = dir.list();
        for (int i=0; i<children.length; i++) {
            boolean success = deleteDir(new File(dir, children[i]));
            if (!success) {
                return false;
            }
        }
    }

    // The directory is now empty so delete it
    return dir.delete();
}

让我告诉你第一件事你不能删除DCIM文件夹，因为它是一个系统文件夹。当你在手机上手动删除它时，它会删除该文件夹的内容，但不会删除DCIM文件夹。您可以通过以下方法删除其内容:

根据评论更新

File dir = new File(Environment.getExternalStorageDirectory()+"Dir_name_here"); 
if (dir.isDirectory()) 
{
    String[] children = dir.list();
    for (int i = 0; i < children.length; i++)
    {
       new File(dir, children[i]).delete();
    }
}

看到android.os。FileUtils，它隐藏在API 21上

public static boolean deleteContents(File dir) {
    File[] files = dir.listFiles();
    boolean success = true;
    if (files != null) {
        for (File file : files) {
            if (file.isDirectory()) {
                success &= deleteContents(file);
            }
            if (!file.delete()) {
                Log.w("Failed to delete " + file);
                success = false;
            }
        }
    }
    return success;
}

来源:https://android.googlesource.com/platform/frameworks/base/ + /主/核心/ java / android / os / FileUtils.java # 414