Android的文件保存到外部存储 [英] Android saving file to external storage

问题描述

我有创建目录和保存在我的Andr​​oid应用程序的文件给它一个小问题。我使用的这块code要做到这一点：

I have a little issue with creating a directory and saving a file to it on my android application. I'm using this piece of code to do this :

String filename = "MyApp/MediaTag/MediaTag-"+objectId+".png";
File file = new File(Environment.getExternalStorageDirectory(), filename);
FileOutputStream fos;

fos = new FileOutputStream(file);
fos.write(mediaTagBuffer);
fos.flush();
fos.close();

但它抛出一个异常：

But it's throwing an exception :

java.io.FileNotFoundException：/mnt/sdcard/MyApp/MediaCard/MediaCard-0.png（没有这样的文件或目录）

java.io.FileNotFoundException: /mnt/sdcard/MyApp/MediaCard/MediaCard-0.png (No such file or directory)

在该行： FOS =新的FileOutputStream（文件）;

如果我设置文件名：的MyApp / MediaTag - + OBJECTID +它的工作，但如果我尝试创建，将文件保存到其它目录是抛出异常。因此，任何想法，我做错了吗？

If I set the filename to : "MyApp/MediaTag-"+objectId+" it's working, but If I try to create and save the file to an another directory it's throwing the exception. So any ideas what I'm doing wrong?

和另外一个问题：有没有什么办法让我的私人文件，在外部存储使用户无法看到他们在画廊，只有当他连自己的设备作为磁盘驱动器？

And another question: Is there any way to make my files private in external storage so user can't see them in gallery, only if he connect his device as Disk Drive?

推荐答案

使用此功能，以节省您的位图SD卡

Use this function to save your bitmap in SD card

private void SaveImage(Bitmap finalBitmap) {

    String root = Environment.getExternalStorageDirectory().toString();
    File myDir = new File(root + "/saved_images");    
    myDir.mkdirs();
    Random generator = new Random();
    int n = 10000;
    n = generator.nextInt(n);
    String fname = "Image-"+ n +".jpg";
    File file = new File (myDir, fname);
    if (file.exists ()) file.delete (); 
    try {
           FileOutputStream out = new FileOutputStream(file);
           finalBitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);
           out.flush();
           out.close();

    } catch (Exception e) {
           e.printStackTrace();
    }
}

和清单中添加此

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

编辑：使用这条线，你可以看到在画廊查看保存的图片

By using this line you can able to see saved images in the gallery view.

sendBroadcast(new Intent(
Intent.ACTION_MEDIA_MOUNTED,
            Uri.parse("file://" + Environment.getExternalStorageDirectory())));

看看这个链接也<一href="http://rajareddypolam.word$p$pss.com/?p=3&$p$pview=true">http://rajareddypolam.word$p$pss.com/?p=3&$p$pview=true

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