Question

我正在尝试从互联网上下载文件，但现在却成功了我想检查文件是否存在于内部存储器中。

else if (arg0.getId() == R.id.btn_download)
{
    Toast.makeText(this, "download button clicked", Toast.LENGTH_SHORT).show();

    DownloadManager.Request request = new DownloadManager.Request(Uri.parse(names[b]));
    request.setDescription("Downloading..");
    request.setTitle("Futsing Magazine Issue " + (this.mPictureManager.getCurrentIndex() +1) );
    // in order for this if to run, you must use the android 3.2 to compile your app
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
        request.allowScanningByMediaScanner();
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
    }
    request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "Futsing Magazine Issue " + (this.mPictureManager.getCurrentIndex()
            +1) +".pdf");

    // get download service and enqueue file
    DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
    manager.enqueue(request);

检索到的项目将下载到/ mnt / sdcard / Download。如何使用代码检查文件是否存在？

Answer 1

假设以下是您文件的路径

String path=context.getFilesDir().getAbsolutePath()+"/filename";
File file = new File ( path ); 

if ( file.exists() ) 
{
     // Toast File is exists
}
else
{
     // Toast File is not exists
}

Answer 2

File applictionFile =  new File(Environment.getExternalStoragePublicDirectory(
                                    Environment.DIRECTORY_DOWNLOADS)+ "/"+<file-name>);

    if(applictionFile != null && applictionFile.exists()){

   }

如果文件正在下载到默认的donwload目录

如何检查内存中是否有文件可用

2 个答案: