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());
}

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'  

你可以像这样递归地删除文件和文件夹:

void deleteRecursive(File fileOrDirectory) {
    if (fileOrDirectory.isDirectory())
        for (File child : fileOrDirectory.listFiles())
            deleteRecursive(child);

    fileOrDirectory.delete();
}

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());
}

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");
    }
}

有很多答案，但我决定加上我自己的，因为它有点不同。它是基于OOP的;)

我创建了DirectoryCleaner类，每当我需要清理某个目录时，它都会帮助我。

public class DirectoryCleaner {
    private final File mFile;

    public DirectoryCleaner(File file) {
        mFile = file;
    }

    public void clean() {
        if (null == mFile || !mFile.exists() || !mFile.isDirectory()) return;
        for (File file : mFile.listFiles()) {
            delete(file);
        }
    }

    private void delete(File file) {
        if (file.isDirectory()) {
            for (File child : file.listFiles()) {
                delete(child);
            }
        }
        file.delete();

    }
}

可以用下面的方法来解决这个问题:

File dir = new File(Environment.getExternalStorageDirectory(), "your_directory_name");
new DirectoryCleaner(dir).clean();
dir.delete();