Java 在 android 中访问 USB 大容量存储设备
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Get access to USB mass storage device in android
提问by
So I have this little cable that you plug into your phone that has a USB port on the other side where you can plug in a flash drive for example, as you can see here:
所以我有一条小电缆，你可以将它插入手机，它的另一侧有一个 USB 端口，你可以在那里插入闪存驱动器，例如，如下所示：
When I plug in a flash drive I get a notification that says:
当我插入闪存驱动器时，我收到一条通知，内容为：
USB mass storage connected
已连接 USB 大容量存储设备
When I then launch a file explorer app I can see that the drive is then located at:
然后当我启动文件资源管理器应用程序时，我可以看到驱动器位于：
/storage/UsbDriveA/
/存储/UsbDriveA/
And that's great, but I want to know how to gain access to the flash drive in my code. Getting access to the SD card is easy enough:
这很好，但我想知道如何在我的代码中访问闪存驱动器。访问 SD 卡很容易：
File sdCard = Environment.getExternalStorageDirectory();
File directory = new File (sdCard.getAbsolutePath() + "/MyFiles")
directory.mkdirs();
But how would you do this in the case of the flash drive? Thanks in advance! :)
但是在闪存驱动器的情况下，您将如何做到这一点？提前致谢！:)
采纳答案by JBA
In this example I am using the FileUtils from Apache, but event without it you will see the logic used to read a USB Flash drive:
在这个例子中，我使用了来自 Apache 的 FileUtils，但如果没有它，您将看到用于读取 USB 闪存驱动器的逻辑：
private UsbManager usbManager;
private UsbDevice clef;
ArrayList<File> images;
usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
clef = null;
if (usbManager != null)
{
HashMap<String,UsbDevice> deviceList = usbManager.getDeviceList();
if (deviceList != null)
{
Iterator<UsbDevice> deviceIterator = deviceList.values().iterator();
while (deviceIterator.hasNext()) {
clef = deviceIterator.next();
}
}
}
if (clef != null)
{
File directory = new File("/storage/UsbDriveA/");
if (directory != null) {
if (directory.canRead()) {
images = new ArrayList<File>();
String[] imageExtensions = {"jpg","jpeg","png","gif","JPG","JPEG","PNG","GIF"};
Iterator<File> iterateImages = FileUtils.iterateFiles(directory, imageExtensions, true);
while (iterateImages.hasNext()) {
File theImage = iterateImages.next();
if (!theImage.getName().startsWith(".", 0))
images.add(theImage);
}
// custom process / methods... not very relevant here :
imageIndex = 0;
scale = 1.0f;
countImgs = images.size();
loadImage(imageIndex);
}
}
}
In my manifest I have those lines, although I'm not sure they're all mandatory...
在我的清单中，我有这些行，虽然我不确定它们都是强制性的......
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-feature android:name="android.hardware.usb.host" />
<uses-permission android:name="android.permission.USB_PERMISSION" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />
回答by ballesta25
I can't test this, not having such a cable myself, but my assumption would be that you can pass your filepath directly into the constructor which would look like:
我无法对此进行测试，我自己没有这样的电缆，但我的假设是您可以将文件路径直接传递到构造函数中，如下所示：
File directory = new File("/storage/UsbDriveA/");
Have you tried this?
你试过这个吗？
