Question

I have an app that needs to display some PDF files. The files are local to the device and the device is used in high-security locations with no web access.

Until Android gets some native ability or libraries to display a PDF file I’m relying on the AdobeReader.apk, which I fire off thusly:

Intent i = new Intent(Intent.ACTION_VIEW);
i.setDataAndType(Uri.fromFile(dgfile), "application/pdf");
i.setClassName("com.adobe.reader", "com.adobe.reader.AdobeReader");
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
// ctx is a passed-in Context of my main Activity
try   { 
    ctx.startActivity(i);
}
 catch (ActivityNotFoundException e)    {   // incase no viewer installed
    Log.e("DG_External", "No viewer found!");
}

This works perfectly, but after I’m done displaying I want to stop it and return to my main app. The ‘winning’ answer on this S.O question said if I used a StartActivityForresult() I could do it with a finishActivity() But I couldn’t get it to work (I don’t see how it could work since there’s no instance of the Activity we want to stop)

Still, I changed my StartActivity to:

((Activity)ctx).startActivityForResult(i, 33);  //!!  // 33 = arbitrary r.c.

This invoked the Adobe reader just fine, but doing a …

((Activity)ctx).finishActivity(33);

…produced no result. I tried wrapping it in try/catch and there were no exceptions thrown.

What am I doing wrong and how do I do this right? Thanks in advance!

Answer 1

Another way to think about this is how can I bring my app to the top of the display and move AdobeReader to the background?

Call startActivity() on one of your activities. Something in your app is determining that “the user on the PC closes a document”. That something can call startActivity().