如何在SD卡上自动创建目录 [英] How to create directory automatically on SD card

问题描述

我正在尝试将我的文件保存到以下位置
FileOutputStream fos = new FileOutputStream("/sdcard/Wallpaper/"+fileName);但我收到异常 java.io.FileNotFoundException
但是，当我将路径设置为 "/sdcard/" 时，它可以工作.

I'm trying to save my file to the following location
FileOutputStream fos = new FileOutputStream("/sdcard/Wallpaper/"+fileName); but I'm getting the exception java.io.FileNotFoundException
However, when I put the path as "/sdcard/" it works.

现在我假设我无法通过这种方式自动创建目录.

Now I'm assuming that I'm not able to create directory automatically this way.

有人可以建议如何使用代码创建目录和子目录?

Can someone suggest how to create a directory and sub-directory using code?

推荐答案

如果你创建了一个 File 包装顶级目录的对象，您可以将其称为 mkdirs() 方法来构建所有需要的目录.类似的东西:

If you create a File object that wraps the top-level directory you can call it's mkdirs() method to build all the needed directories. Something like:

// create a File object for the parent directory
File wallpaperDirectory = new File("/sdcard/Wallpaper/");
// have the object build the directory structure, if needed.
wallpaperDirectory.mkdirs();
// create a File object for the output file
File outputFile = new File(wallpaperDirectory, filename);
// now attach the OutputStream to the file object, instead of a String representation
FileOutputStream fos = new FileOutputStream(outputFile);

注意:使用 Environment.getExternalStorageDirectory() 用于获取SD 卡"目录，因为如果手机带有 SD 卡以外的其他东西(例如内置闪存，a'laiPhone).无论哪种方式，您都应该记住，您需要检查以确保它确实在那里，因为 SD 卡可能会被移除.

Note: It might be wise to use Environment.getExternalStorageDirectory() for getting the "SD Card" directory as this might change if a phone comes along which has something other than an SD Card (such as built-in flash, a'la the iPhone). Either way you should keep in mind that you need to check to make sure it's actually there as the SD Card may be removed.

更新:从 API 级别 4 (1.6) 开始，您还必须请求权限.像这样(在清单中)应该可以工作:

UPDATE: Since API Level 4 (1.6) you'll also have to request the permission. Something like this (in the manifest) should work:

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

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