CODEWITHSUNDEEP
javaandroid
wikki
wikki

Reputation: 35

Is it possible to wait for activity results?

I made a desktop version for encrypting and decrypting files, my boss was very excited so he gave me the task to make an app out of it.

Activity A has two buttons on it, one for encryption and one for decryption. When the user presses one of the buttons an "pickfile" intent comes up:

Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
intent.setType("file/*.*");
startActivityForResult(intent, PICKFILE_RESULT_CODE);

Then I have the Result Method:

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data)
    {
        switch (requestCode)
        {
            case PICKFILE_RESULT_CODE:
                if (resultCode == RESULT_OK)
                {
                     Pfad = data.getData().getPath();
                }
        }
    }

My hope was that I can use the "Pfad" variable directly after calling startActivityForResult(intent, PICKFILE_RESULT_CODE);but the compiler shows me an error that "Pfad" is NULL. I also noticed that the app executes the code which comes after the startActivityForResult() directly, but also the pickfile dialog comes up for a sec?

Can some one help me out here? Thank you a lot!

EDIT I forgot to set the variables, but now a new error appears... after I call "startAcitivityForResult()" I directly call my method "setVariables(..)" which trims the path I got from the result Method... heres my method:

private void setVariables(int i, String fullFileName)
    {
        String tmp = "";

        if(i == 1) //verschlüsseln
        {
            ext = fullFileName.substring(fullFileName.lastIndexOf(".")).toLowerCase();
            tmp = fullFileName.substring(0, fullFileName.toLowerCase().lastIndexOf(ext));
        }
        else if(i == 2) //entschlüsseln
        {
            ext = fullFileName.substring(fullFileName.lastIndexOf(".")).toLowerCase();
            if(ext.equals(encryptExt))
            {
                tmp = fullFileName.substring(0, fullFileName.toLowerCase().lastIndexOf(encryptExt));
                ext = tmp.substring(tmp.lastIndexOf("."));
                tmp = fullFileName.substring(0, fullFileName.toLowerCase().lastIndexOf(ext + encryptExt));

            }
        }

        Path = tmp.substring(0, tmp.lastIndexOf("\\")+1);
        fileNameOrig = tmp.substring(Path.length(), tmp.length());
        fileNameEncrypt = fileNameOrig;
    }

The debugger fires me an error that the lenght of my variable "Pfad" (which stands for path, I have no idea why I made it german xD) is 0.

As I said, it seems that the "startActivityForResult" dosent pause my main activity, because I can´t choose any file, it directly goes to the "setVariables" method?

Btw. the button event handlers are inside the onCreate() Method of the main activity, maybe this causes the error?

Upvotes: 0

Views: 2352

Answers (1)

B. Kemmer
B. Kemmer

Reputation: 1537

startActivityForResult is of course starting another Activity. So the Activity you are working on should normally get paused. You then get a File-Picker.
After you chose a File, you will get into onActivityResult which is more or less a Callback-Function.

So your variable Pfad will get defined inside of the Callback, but not previously, so it is null.

If you don't understand my answer, just read the Android Documentation.

Upvotes: 4

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