如何在SD卡中自动生成目录 [英] How to create directory automatically on SD card

问题描述

我想我的文件保存到以下位置 - 的FileOutputStream FOS =新的FileOutputStream（/ SD卡/壁纸/+文件名）; 但我发现兴田异常 java.io.FileNotFoundException
但是，当我把路径/ SD卡/它的工作原理。

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

现在我假设我不能够自动创建目录这种方式。

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

有人建议如何创建一个通过code目录和子目录？

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

推荐答案

如果您创建一个文件对象包装了顶级目录，你可以调用它的 mkdirs（）的方法来构建所有必需的目录。是这样的：

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：这可能是明智的使用<一个href="http://developer.android.com/reference/android/os/Environment.html#getExternalStorageDirectory%28%29">Environment.getExternalStorageDirectory()为让SD卡的目录，因为这如果这款手机可能会改变沿线有东西比SD卡等（如内置闪光灯，a'la的iPhone）。无论哪种方式，你应该记住，你需要检查，以确保它实际上是有作为的SD卡可能会被删除。

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：由于API级别4（1.6），你也有要求的权限。像这样的东西（在清单）应该工作：

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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