我不明白为什么人们说这是保存在外部存储器,因为当我使用这个代码,我签入我的SD卡没有文件

代码这个

OutputStream imageFileOS;
        int imageNum = 0;
        Intent imageIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
        File imagesFolder = new File(Environment.getExternalStoragePublicDirectory( Environment.DIRECTORY_PICTURES),"Punch");
        if(!imagesFolder.exists()){
            imagesFolder.mkdirs(); // <----
        }
        String fileName = "image_" + String.valueOf(imageNum) + ".jpg";
        File output = new File(imagesFolder,fileName);
        while (output.exists()){
            imageNum++;
            fileName = "image_" + String.valueOf(imageNum) + ".jpg";
            output = new File(imagesFolder,fileName);
        }
        Uri uriSavedImage = Uri.fromFile(output);
        imageIntent.putExtra(MediaStore.EXTRA_OUTPUT,uriSavedImage);

当我运行代码并检查时,它有“内存/图片/打孔/图像_0.jpg”中的文件
但在SD卡中看不到(SD卡=外部存储卡16 GB)
请帮我 ..

我认为你对getExternalStorageDirectory的作用感到困惑.

它获取由设备制造商指定的主存储目录.这通常是“sdcard”.注释中指定的“External_sd”实际上是辅助存储目录,不会在给定方法中返回.

这仍然不是受保护的内部存储,并且可以在连接时由Pcs安装和访问.

来自android文档：

Note: don’t be confused by the word “external” here. This directory can better be thought as media/shared storage. It is a filesystem that can hold a relatively large amount of data and that is shared across all applications (does not enforce permissions). Traditionally this is an SD card,but it may also be implemented as built-in storage in a device that is distinct from the protected internal storage and can be mounted as a filesystem on a computer.

我需要将使用我的应用程序拍摄的照片保存在特定文件夹中.我已经阅读了很多这个问题的解决方案,但我无法使它们中的任何一个工作,所以我寻求帮助.

MainActivity.java

public void onClick(View v) {

    Intent camera = new Intent(
            android.provider.MediaStore.ACTION_IMAGE_CAPTURE);

    //Folder is already created
    String dirName = Environment.getExternalStorageDirectory().getPath()
            + "/MyAppFolder/MyApp" + n + ".png";

    Uri uriSavedImage = Uri.fromFile(new File(dirName));
    camera.putExtra(MediaStore.EXTRA_OUTPUT,uriSavedImage);
    startActivityForResult(camera,1);

    n++;
}

AndroidManifest.xml中

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

通过以下代码,它对我来说很好.

private void createDirectoryAndSaveFile(Bitmap imagetoSave,String fileName) {

    File direct = new File(Environment.getExternalStorageDirectory() + "/DirName");

    if (!direct.exists()) {
        File wallpaperDirectory = new File("/sdcard/DirName/");
        wallpaperDirectory.mkdirs();
    }

    File file = new File(new File("/sdcard/DirName/"),fileName);
    if (file.exists()) {
        file.delete();
    }
    try {
        FileOutputStream out = new FileOutputStream(file);
        imagetoSave.compress(Bitmap.CompressFormat.JPEG,100,out);
        out.flush();
        out.close();
    } catch (Exception e) {
        e.printstacktrace();
    }
}