资源复制到SD卡给出的Andr​​oid损坏的文件 [英] copying resource to sdcard gives a damaged file in android

问题描述

我试图用这个code从应用程序移动原料资源（这是一个zip文件），以SD卡：

I am trying to move a raw resource (it is a zip file) from the app to SD card using this code:

void copyFile() throws IOException {
    File dest = Environment.getExternalStorageDirectory();
    InputStream in = context.getResources().openRawResource(R.raw.file);
    OutputStream out = new FileOutputStream(dest + "/file.zip");

    // Transfer bytes from in to out
    byte[] buf = new byte[1024];
    int len;
    while ((len = in.read(buf)) > 0) {
        out.write(buf, 0, len);
    }
    in.close();
    out.close();
}

然而，当我检查SD卡上的文件，我得到的消息：
归档或者是未知格式或已损坏

However, when I check the file on the sd card I get the message: "The archive is either in an unknown format or damaged"

为什么文件没有正确复制？

Why is the file not being copied properly?

推荐答案

我在你的code做了一些小改动：

I made some little modifications on your code:

File dest = Environment.getExternalStorageDirectory();
InputStream in = context.getResources().openRawResource(R.raw.file);
// Used the File-constructor
OutputStream out = new FileOutputStream(new File(dest, "file.zip"));

// Transfer bytes from in to out
byte[] buf = new byte[1024];
int len;
try {
    // A little more explicit
    while ( (len = in.read(buf, 0, buf.length)) != -1){
         out.write(buf, 0, len);
    }
} finally {
    // Ensure the Streams are closed:
    in.close();
    out.close();
}

这一次为我工作（而不是在Android，但一个正常的计算机上）。这些修改我在其中：

This one worked for me (not on Android but on a normal computer). The modifications I made where:

• 我用<一个href=\"http://download.oracle.com/javase/6/docs/api/java/io/File.html#File%28java.io.File,%20java.lang.String%29\"相对=nofollow> 文件 -constructor 的<一个href=\"http://download.oracle.com/javase/1.4.2/docs/api/java/io/FileOutputStream.html#FileOutputStream%28java.io.File%29\"相对=nofollow> 的FileOutputStream 。


• 我用了一个的try-catch - 块，以确保流越来越
  封闭的，即使是在读取/写入错误/异常。


• 我用了更明确的<一个href=\"http://download.oracle.com/javase/6/docs/api/java/io/InputStream.html#read%28byte%5B%5D,%20int,%20int%29\"相对=nofollow> 读 -method （这基本上是
  你的一样），因为我感觉好多了，当我告诉他该怎么做。

• I used the File-constructor for the FileOutputStream.
• I used a try-catch-block to ensure that the Streams are getting closed, even when there is an error/exception while reading/writing.
• I used the more explicit read-method (which is basically the same as yours) because I feel better when I tell him what to do.

正如我前面所说，我试了一下我的电脑上，它的工作。证明：

As I said above, I tried it on my computer and it worked. Proof:

[luke@KeksDose Downloads]$ md5sum quick_action.zip 
4e45fa08f24e971961dd60c3e81b292d  quick_action.zip
[luke@KeksDose Downloads]$ md5sum quick_action_copy.zip 
4e45fa08f24e971961dd60c3e81b292d  quick_action_copy.zip

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