Returning through multiple functions

Question

Alright, this might be kinda simple, but I cannot figure out how to do this. How can I change this function to return the String class_name? I know that I need to change the function from void to String, but what else do I need to do?

Much appreciated!

public void addClass() {
    AlertDialog.Builder alert = new AlertDialog.Builder(this);  

    alert.setTitle("Add Class");

    final EditText input = new EditText(this);  
    alert.setView(input);  

    alert.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {  
        public void onClick(DialogInterface dialog, int whichButton) {  
            String class_name = input.getText().toString();
        }  
    });  

    alert.setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {  
        public void onClick(DialogInterface dialog, int whichButton) {  
        }  
    });  

    alert.show();
}

Answer 1

The behavior (a synchronous dialog) you are trying to get deliberately does not exist in android. Whatever you want to happen when the dialog button is clicked has to be placed in the OnClickListener.OnClick method.

Answer 2

Assuming alert.show does not return until input.getText() contains the entered value, you could try:

public void addClass() {
   final Vector<String> retval = new Vector<String>();
   retval.add("");

   ...
   ...
     alert.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {  
          public void onClick(DialogInterface dialog, int whichButton) {  
            String class_name = input.getText().toString();
            retval.set(0,class_name);
      }  
});  

...
...

  return retval.get(0);
}

Answer 3

AlertDialog is asynchronous and therefore what you want to achieve is not possible through that code. you could set String class_name as global ad then initialize it to

class_name = input.getText().toString();

inside the onClick method of alert Button.

Answer 4

Returning the class_name value doesn't help. You have to implement a callback method that takes the value and performs the required action:

public void addClass() {
    AlertDialog.Builder alert = new AlertDialog.Builder(this);  

    // ...

    alert.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {  
        public void onClick(DialogInterface dialog, int whichButton) {  
            setClassName(input.getText().toString());
        }  
    });  

    // ...
}

protected void setClassName(String class_name) {
  // do what ever has to be done with class_name
}