Question

我有一个字节数组，文件名与文件的类型（如xx.pdf，yy.txt）。我想用这些参数打开文件。我试图保存到某个位置然后打开它。但它没有用。我可以使用FileOutputStream保存它，但我必须将其转换为'File'才能打开它。请在下面找到我的代码。

       public void ViewFile(String fileName,String base64File) throws IOException {

            FileOutputStream fos = openFileOutput(fileName,Context.MODE_PRIVATE);
            fos.write(base64File.getBytes());

            fos.close();

            // here is the code to open file and i have to send as 'File'
           // openFile(getApplicationContext(),file);

    }

  public void openFile(Context context, File url) throws IOException {
    // Create URI

    Uri uri = Uri.fromFile(url);

    Intent intent = new Intent(Intent.ACTION_VIEW);
    // Check what kind of file you are trying to open, by comparing the url with extensions.
    // When the if condition is matched, plugin sets the correct intent (mime) type,
    // so Android knew what application to use to open the file
    if (url.toString().contains(".doc") || url.toString().contains(".docx")) {
        // Word document
        intent.setDataAndType(uri, "application/msword");
    } else if(url.toString().contains(".pdf")) {
        // PDF file
        intent.setDataAndType(uri, "application/pdf");
    } else if(url.toString().contains(".ppt") || url.toString().contains(".pptx")) {
        // Powerpoint file
        intent.setDataAndType(uri, "application/vnd.ms-powerpoint");
    } else if(url.toString().contains(".xls") || url.toString().contains(".xlsx")) {
        // Excel file
        intent.setDataAndType(uri, "application/vnd.ms-excel");
    } else if(url.toString().contains(".zip") || url.toString().contains(".rar")) {
        // WAV audio file
        intent.setDataAndType(uri, "application/x-wav");
    } else if(url.toString().contains(".rtf")) {
        // RTF file
        intent.setDataAndType(uri, "application/rtf");
    } else if(url.toString().contains(".wav") || url.toString().contains(".mp3")) {
        // WAV audio file
        intent.setDataAndType(uri, "audio/x-wav");
    } else if(url.toString().contains(".gif")) {
        // GIF file
        intent.setDataAndType(uri, "image/gif");
    } else if(url.toString().contains(".jpg") || url.toString().contains(".jpeg") || url.toString().contains(".png")) {
        // JPG file
        intent.setDataAndType(uri, "image/jpeg");
    } else if(url.toString().contains(".txt")) {
        // Text file
        intent.setDataAndType(uri, "text/plain");
    } else if(url.toString().contains(".3gp") || url.toString().contains(".mpg") || url.toString().contains(".mpeg") || url.toString().contains(".mpe") || url.toString().contains(".mp4") || url.toString().contains(".avi")) {
        // Video files
        intent.setDataAndType(uri, "video/*");
    } else {
        //if you want you can also define the intent type for any other file

        //additionally use else clause below, to manage other unknown extensions
        //in this case, Android will show all applications installed on the device
        //so you can choose which application to use
        intent.setDataAndType(uri, "*/*");
    }

    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    context.startActivity(intent);
}

Answer 1

我试图保存到某个位置，然后将其打开。但这没用

我认为应该。为什么不起作用？

通过略过这段代码，您似乎将内容保存到了文件中，该文件可能位于应用程序的私有空间中。

因此，当您启动该意图时，尝试读取该意图的其他应用程序可能没有访问权限。

只是预感。

如何从android中的字节数组中打开文件？

1 个答案: