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();

这(尝试删除所有子文件和子目录，包括提供的目录):

如果是文件，删除 如果是空目录，请删除 如果不是空目录，再次调用删除子目录，重复1到3

例子:

File externalDir = Environment.getExternalStorageDirectory()
Utils.deleteAll(externalDir); //BE CAREFUL.. Will try and delete ALL external storage files and directories

访问“外部存储目录”需要具备以下权限:

(使用ContextCompat。checkSelfPermission和ActivityCompat.requestPermissions)

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

递归方法:

public static boolean deleteAll(File file) {
    if (file == null || !file.exists()) return false;

    boolean success = true;
    if (file.isDirectory()) {
        File[] files = file.listFiles();
        if (files != null && files.length > 0) {
            for (File f : files) {
                if (f.isDirectory()) {
                    success &= deleteAll(f);
                }
                if (!f.delete()) {
                    Log.w("deleteAll", "Failed to delete " + f);
                    success = false;
                }
            }
        } else {
            if (!file.delete()) {
                Log.w("deleteAll", "Failed to delete " + file);
                success = false;
            }
        }
    } else {
        if (!file.delete()) {
            Log.w("deleteAll", "Failed to delete " + file);
            success = false;
        }
    }
    return success;
}

最快最简单的方法:

public static boolean deleteFolder(File removableFolder) {
        File[] files = removableFolder.listFiles();
        if (files != null && files.length > 0) {
            for (File file : files) {
                boolean success;
                if (file.isDirectory())
                    success = deleteFolder(file);
                else success = file.delete();
                if (!success) return false;
            }
        }
        return removableFolder.delete();
}

这是另一种(现代)解决方法。

public class FileUtils {
    public static void delete(File fileOrDirectory) {
        if(fileOrDirectory != null && fileOrDirectory.exists()) {
            if(fileOrDirectory.isDirectory() && fileOrDirectory.listFiles() != null) {      
                Arrays.stream(fileOrDirectory.listFiles())
                      .forEach(FileUtils::delete);
            }
            fileOrDirectory.delete();
        }
    }
}

从API 26开始在Android上运行

public class FileUtils {

    public static void delete(File fileOrDirectory)  {
        if(fileOrDirectory != null) {
            delete(fileOrDirectory.toPath());
        }
    }

    public static void delete(Path path)  {
        try {
            if(Files.exists(path)) {
                Files.walk(path)
                        .sorted(Comparator.reverseOrder())
                        .map(Path::toFile)
//                      .peek(System.out::println)
                        .forEach(File::delete);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

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()

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
    }