我的应用程序复制的文件未显示在PC上 [英] Files copied by my app not showing up on PC

问题描述

我正在尝试在应用程序中运行简单的数据库备份，但是当我将设备连接到PC时文件没有显示，但是在Android File Manager中似乎可以.该文件正在通过以下方式复制到下载"文件夹中...

I'm trying to run a simple database backup in my application, but the files are not showing up when I connect the device to my PC, but appears to be OK in the Android File Manager. The file is being copied to "Downloads" folder by the way...

这是我要复制的代码:

//...
private void backupDatabase(){

    String downloadsPath = Environment
            .getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)
            .getAbsolutePath();
    String backupDirectoryPath = downloadsPath+"/myapp_backups/";
    File backupDirectory = new File(backupDirectoryPath);
    backupDirectory.mkdirs();

    String bkpFileName = "backup_"+(new Date().getTime())+".bkp";

    String src = mContext.getDatabasePath(DatabaseHelper.DATABASE_NAME).getAbsolutePath();
    String dest = backupDirectoryPath + bkpFileName;
    FileUtil.copyFile(src, dest);

}
//...

这是 FileUtil.copyFile 函数的样子:

public static boolean copyFile(String src, String dest){

    boolean success;

    try{
        if(!isFile(src)){
            throw new Exception("Source file doesn't exist: "+src);
        }

        InputStream in = new FileInputStream(src);
        OutputStream out = new FileOutputStream(dest);

        // 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();

        success = true;
    }catch (Exception exception){
        exception.printStackTrace();
        success = false;
    }

    return success;

}

该代码在我们测试过的两种设备上均有效，但都无法在PC上显示该文件.

The code works on both devices we tested but none shows the file on the PC.

我想念什么?

推荐答案

正如@CommonsWare链接的问题所指出的那样，我对 MediaScannerConnection 类进行了一些研究，并解决了该问题.

As pointed out in the question linked by @CommonsWare, I made a little research about MediaScannerConnection class and it solved the problem.

这是最终代码:

String downloadsPath = Environment
        .getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)
        .getAbsolutePath();
String backupDirectoryPath = downloadsPath+"/myapp_backups/";
File backupDirectory = new File(backupDirectoryPath);
backupDirectory.mkdirs();

String bkpFileName = "backup_"+(new Date().getTime())+".bkp";

String src = mContext.getDatabasePath(DatabaseHelper.DATABASE_NAME).getAbsolutePath();
String dest = backupDirectoryPath + bkpFileName;
FileUtil.copyFile(src, dest);

//Scan the new file, so it will show up in the PC file explorer:
MediaScannerConnection.scanFile(
    mContext, new String[]{dest}, null, null
);

这篇关于我的应用程序复制的文件未显示在PC上的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！