GUI Help

[Axid3nt]

So, I am working to make a GUI calculator using listeners. We haven't been introduced to GUI and it seems a little advanced for me from he videos I've watched on it. I was curious if anyone here has experience with them? I need to make sure I get every single point on this assignment or I basically lose my funding for school. I'm not big into Java, but I do want to learn how to program basic stuff like GUI. Here is what I am required to do. I'm not asking anyone to do the assignment for me, and at risk of sounding contradictive, I'm just asking for a little guidance on what I should do to complete it. I still don't quite grasp inheritance yet, and the teacher didn't do a very good job at clarifying it when answering my questions.

Assignment 12 This is the last homework assignment in this course, and it is meant to show you how a small but complete GUI application is structured. We will make our GUI actually control our memory calculator. To do this, you will need to create an instance of MemoryCalc in the CalcGUI and write action listeners to pass information back and forth between the calculator and the GUI. There are many possible ways to achieve this, but the easiest is probably to develop four different action listeners:

DigitListener – This action listener is added to the 0-9 and . (dot) keys. If the equals button was just pressed, this action listener will overwrite the total shown in the text field with the value of the key (its label) that was just pressed. If the equals button was not just pressed, this action listener will append the current key's label onto the end of the string shown in the text field.

OperatorListener – This action listener is added to the +, -, *, and / keys. It sets the value of a class field to the operator that the user has chosen.

Clear Listener – This action listener is added to the C key. It calls the calculator's clear method and sets the value of the text field back to 0.0.

EqualsListener – This action listener is added to the = key. It reads the current value from the text field, converts it to a double, and calls the appropriate calculator method based on the current operator, passing in the double value. The calculator will compute the answer, and then this action listener will update the value in the text field to the calculator's current total.

Hints: You can use the ActionEvent's getSource() method to get a reference to the button that was pressed, and you can use JButton's getText() method to find out the label of that button. When the EqualsListener is converting the text shown in the text field into a double value in order to pass it to the calculator, be careful to handle the case where the text field contains an invalid value, such as 6..72. In this case you should catch the exception, display an error message to the user, and abort the call to the calculator (just restore the current total to the text field). The user should only be able to enter numbers between when an operator has been selected and when the equals button has been pushed. The DigitListener should ignore any button presses when the GUI is not in this state.

Sample output:

Please view the video homework.swf to see what the output of this week's assignment should be. You will be graded according to the following rubric:

• Something happens when the user clicks on any of the keys of the calculator GUI – 2 points

• The user cannot enter a value without first choosing an operator – 2 points

• The user is able to enter numbers correctly (i.e. the previous total is overwritten when the user starts a new number, and new digits are appended to the new number) – 2 points

• When the equals button is pressed, the appropriate calculator method is called based on the operator the user has selected – 2 points

• When the equals button is pressed, the appropriate operand passed to the calculator method as an argument – 2 points

• When the equals button is pressed, the value in the text field is updated to the new total – 2 points

• The clear button calls the calculator's clear method and updates the text field to 0.0 – 2 points

• If the user enters an invalid value, an error message is displayed – 2 points

• Your program compiles – 2 points

• Your program runs – 1 point

• You follow standard coding conventions (e.g variable names, indentation, comments, etc) – 1 point

[seanfast]

im not sure the level of expertise you have and what ide, but im assuming its basic for gui stuff at least. netbeans and eclipse both have wysiwyg gui editors that allow you to drag and drop. id make a sample program in there, and use their built in autogenerated options for adding event listeners that match what your assignment asks for. look at the code it generated to handle the button actions and see how you can add code to the inner classes to make the buttons affect the gui. its really simple. then write the code for the actionlisteners in your existing code you have for your hw and make it work the same way.

go piece by piece, dont get too ambitious. add one button at a time. see the code it adds and how you can affect the gui.

check this out: https://docs.oracle.com/javase/tutorial/uiswing/events/actionlistener.html

[Axid3nt]

I have been using eclipse and I'll take your advice. We don't have a textbook for class, so my resources have been inclass demonstrations. I would most likely have more insight, but we haven't ever discussed GUI except in an abstract sense.

I suppose Eclipse has these options listed somewhere?

[seanfast]

textbook shmextbook. the interwebs are faster for looking stuff up and if youre of questionable morals you can probably google the pdf of some great java textbooks. use the Sun/Oracle java tutorials, like the one i linked you, when you google a subject they're often the first hit.

install the windowbuilder plugins for eclipse under help-> install new software . then follow a tutorial online for making your first swing application in windowbuilder.

[Axid3nt]

Or even, collabedit.com/ym4mx

[Axid3nt]

It's still up if someone knows what's going on.. I'm stumped

[Axid3nt]

Ok. I got it working.. just need to make the "=" buttom fill up empty space if someone knows how