Swing，JDK 7中的GUI异常

Question

I'm relatively new to Java and attempting to get my first exposure using Swing, and so I've decided to mock up a calculator in Java using Swing and JButtons / JTextFields .

Problem being, most buttons display correctly and at the correct sizes, but there are a few abnormalities - particularly, the subtraction (-) button doesn't appear and the equation button (=) appears behind the others. Would post an image, but that should be sufficient and my rep won't allow me to inline an image; I lost an older account I had on here and have to suffer the consequences.

Without further ado, here's the code:

// Set the display JTextField as the top element in the GUI stackup:
    disp.setBounds(50,25,400,50);


    button7.setBounds(50,75,x,y);
    button8.setBounds(150,75,x,y);
    button9.setBounds(250,75,x,y);
    buttonPlus.setBounds(350,75,x,y);
    button4.setBounds(50,125,x,y);
    button5.setBounds(150,125,x,y);
    button6.setBounds(250,125,x,y);
    buttonMinus.setBounds(350,75,x,y);
    button1.setBounds(50,175,x,y);
    button2.setBounds(150,175,x,y);
    button3.setBounds(250,175,x,y);
    buttonMult.setBounds(350,175,x,y);
    buttonClear.setBounds(50,225,x,y);
    button0.setBounds(150,225,x,y);
    buttonEqual.setBounds(250,225,x,y);
    buttonDiv.setBounds(350,225,x,y);

    frame.add(disp);
    frame.add(button0);
    frame.add(button1);
    frame.add(button2);
    frame.add(button3);
    frame.add(button4);
    frame.add(button5);
    frame.add(button6);
    frame.add(button7);
    frame.add(button8);
    frame.add(button9);
    frame.add(buttonClear);
    frame.add(buttonPlus);
    frame.add(buttonMinus);
    frame.add(buttonMult);
    frame.add(buttonDiv);
    frame.add(buttonEqual);

    //Display the window.
    frame.pack();
    frame.setVisible(true);

If it's relevant, I'll proceed to post the constructors as well; I'm using IntelliJ IDEA if that's of any pertinence.

Answer 1

In your code, buttonMinus has exactly the same bounds as buttonPlus . No doubt an innocent cut-and-paste error.

I don't know what you mean when you say the equals button is behind the others; is it totally obscured by them? Partly obscured? Is it appearing in the correct row? Is it too wide? Too narrow?

Ultimately, it doesn't matter. Andrew is right; using a layout manager will prevent these headaches and many others, including the aforementioned cut-and-paste error:

JPanel buttonPanel = new JPanel(new GridLayout(0, 4, 3, 3));
buttonPanel.add(button7);
buttonPanel.add(button8);
buttonPanel.add(button9);
buttonPanel.add(buttonPlus);
buttonPanel.add(button4);
buttonPanel.add(button5);
buttonPanel.add(button6);
buttonPanel.add(buttonMinus);
buttonPanel.add(button1);
buttonPanel.add(button2);
buttonPanel.add(button3);
buttonPanel.add(buttonMult);
buttonPanel.add(buttonClear);
buttonPanel.add(button0);
buttonPanel.add(buttonEqual);
buttonPanel.add(buttonDiv);

I get that you wanted to proceed in small steps, but the simpler LayoutManagers (GridLayout, BorderLayout, FlowLayout, and BoxLayout) are a step that you should not skip/postpone.