在Android中使用Intent无法从SD卡打开文件

Question

I tried many ways to open file but I'm not able to open file from sd-card using intent.

From internal memory easily open file, but from sd-card file open is difficult. Also able to open file from web-url.

Permission :

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

b = true -> file uri

b = false -> web url

url = /mnt/media_rw/9016-4EF8/123.pdf

Here is my code for open file from sd-card:

 public static void openFile(Activity context, String url, Boolean b) throws
 IOException 

{


    File file = new File(url);

    Uri uri=null;


    if (b)
        uri = Uri.fromFile(file);
    else
        uri = Uri.parse(url);


    Intent intent = new Intent(Intent.ACTION_VIEW);


    if (url.toString().toLowerCase().contains(".doc") || url.toString().toLowerCase().contains(".docx")) {
        // Word document
        intent.setDataAndType(uri, "application/msword");
    } else if (url.toString().toLowerCase().contains(".pdf")) {
        // PDF file
        intent.setDataAndType(uri, "application/pdf");
    } else if (url.toString().toLowerCase().contains(".ppt") || url.toString().toLowerCase().contains(".pptx")) {
        // Powerpoint file
        intent.setDataAndType(uri, "application/vnd.ms-powerpoint");
    } else if (url.toString().toLowerCase().contains(".xls") || url.toString().toLowerCase().contains(".xlsx")) {
        // Excel file
        intent.setDataAndType(uri, "application/vnd.ms-excel");
    } else if (url.toString().toLowerCase().contains(".zip") || url.toString().toLowerCase().contains(".rar")) {
        // WAV audio file
        intent.setDataAndType(uri, "application/x-wav");
    } else if (url.toString().toLowerCase().contains(".rtf")) {
        // RTF file
        intent.setDataAndType(uri, "application/rtf");
    } else if (url.toString().toLowerCase().contains(".wav") || url.toString().toLowerCase().contains(".mp3")) {
        // WAV audio file
        intent.setDataAndType(uri, "audio/x-wav");
    } else if (url.toString().toLowerCase().contains(".gif")) {
        // GIF file
        intent.setDataAndType(uri, "image/gif");
    } else if (url.toString().toLowerCase().toLowerCase().contains(".jpg") || url.toString().toLowerCase().contains(".jpeg") || url.toString().toLowerCase().contains(".png")) {
        //JPG file
        intent.setDataAndType(uri, "image/*");
    } else if (url.toString().toLowerCase().contains(".txt")) {
        // Text file
        intent.setDataAndType(uri, "text/plain");
    } else if (url.toString().toLowerCase().contains(".3gp") || url.toString().toLowerCase().contains(".mpg") || url.toString().toLowerCase().contains(".mpeg") || url.toString().toLowerCase().contains(".mpe") || url.toString().toLowerCase().contains(".mp4") || url.toString().toLowerCase().contains(".avi")) {
        // Video files
        intent.setDataAndType(uri, "video/*");
    } else {
        intent.setDataAndType(uri, "*/*");
    }
    //intent.setDataAndType(uri, "application/*");


    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);


    try {
        context.startActivity(intent);
    } catch (ActivityNotFoundException e) {
        e.printStackTrace();
        Log.e("Error -> ", e + "");
    }
}

Output:

File not open using intent

Answer 1

Try using this, 

 File dir    =   new File (Environment.getExternalStorageDirectory().getAbsolutePath() + "/PersonData");
 File file   =   new File(dir, "Data.pdf");

Here "PersonData" is the folder inside sdcard, and the filename is Data.pdf

Answer 2

看来您应该像这样通过Intent传递url：

Intent intent = new Intent(Intent.ACTION_VIEW, uri);

Answer 3

Be sure <uses-permission 's place. It should be like below;

 <manifest>
      <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
      <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
      <application>
             <activity> 
              ...
             </activity>
      </application>
  </manifest> 

Answer 4

You do not have direct filesystem access to arbitrary locations on removable storage , starting with Android 4.4.

Since nothing on Android 4.4+ should be giving you that filesystem path, this normally will not be a problem. It will be a problem if you are hard-coding that path, since you do not have access to that location.