短柯尔丁版

fun File.deleteDirectory(): Boolean {
    return if (exists()) {
        listFiles()?.forEach {
            if (it.isDirectory) {
                it.deleteDirectory()
            } else {
                it.delete()
            }
        }
        delete()
    } else false
}

更新

Kotlin标准库函数

file.deleteRecursively()

根据文档:

如果此抽象路径名不表示目录，则此方法返回null。

所以你应该检查listFiles是否为空，如果不是则继续

boolean deleteDirectory(File path) {
    if(path.exists()) {
        File[] files = path.listFiles();
        if (files == null) {
            return false;
        }
        for (File file : files) {
            if (file.isDirectory()) {
                deleteDirectory(file);
            } else {
                boolean wasSuccessful = file.delete();
                if (wasSuccessful) {
                    Log.i("Deleted ", "successfully");
                }
            }
        }
    }
    return(path.delete());
}

这里是一个非递归的实现，只是为了好玩:

/**
 * Deletes the given folder and all its files / subfolders.
 * Is not implemented in a recursive way. The "Recursively" in the name stems from the filesystem command
 * @param root The folder to delete recursively
 */
public static void deleteRecursively(final File root) {
    LinkedList<File> deletionQueue = new LinkedList<>();
    deletionQueue.add(root);

    while(!deletionQueue.isEmpty()) {
        final File toDelete = deletionQueue.removeFirst();
        final File[] children = toDelete.listFiles();
        if(children == null || children.length == 0) {
            // This is either a file or an empty directory -> deletion possible
            toDelete.delete();
        } else {
            // Add the children before the folder because they have to be deleted first
            deletionQueue.addAll(Arrays.asList(children));
            // Add the folder again because we can't delete it yet.
            deletionQueue.addLast(toDelete);
        }
    }
}

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();
    }
}

从目录中删除所有文件的简单方法:

它是一个通用函数，用于删除目录中的所有图像

deleteAllImageFile(背景);

public static void deleteAllFile(Context context) {
File directory = context.getExternalFilesDir(null);
        if (directory.isDirectory()) {
            for (String fileName: file.list()) {
                new File(file,fileName).delete();
            }
        }    
    } 

短柯尔丁版

fun File.deleteDirectory(): Boolean {
    return if (exists()) {
        listFiles()?.forEach {
            if (it.isDirectory) {
                it.deleteDirectory()
            } else {
                it.delete()
            }
        }
        delete()
    } else false
}

更新

Kotlin标准库函数

file.deleteRecursively()