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javaswingcalculator

Having hard time making equals button to occupy 2 rows in 1 column

JButton btnEq = new JButton("=");
btnEq.setBackground(babyBlue); //to set color of equals btn

my code so far is just adding the button for equal I tried using getcontentpane still not working or I just don't know how to properly use it.enter image description here

Solution

  • You are using GridLayout to arrange your buttons. GridLayout does not support stretching one component over several rows (or columns). You can

    • use a LayoutManager that supports stretching components over multiple rows/columns restructure
    • your component hierarchy to use multiple containers with different layout managers

    to achieve the desired result.

    One solution using the JDK's GridBagLayout might be

        JPanel p2 = new JPanel(new GridBagLayout());
    ... // background, border, etc.

    GridBagConstraints gbc = new GridBagConstraints();
    gbc.anchor = GridBagConstraints.CENTER;
    gbc.fill = GridBagConstraints.BOTH;
    gbc.weightx = 1;
    gbc.weighty = 1;

    gbc.gridx = 0;
    gbc.gridy = 0;
    p2.add(pOnOff, gbc);
    ++gbc.gridx;
    p2.add(btnClr, gbc);
    ++gbc.gridx;
    p2.add(btnDel, gbc);
    ++gbc.gridx;
    p2.add(btnDiv, gbc);

    gbc.gridx = 0;
    ++gbc.gridy;
    p2.add(btnSqrt, gbc);
    ++gbc.gridx;
    p2.add(btnSq, gbc);
    ++gbc.gridx;
    p2.add(btnInv, gbc);
    ++gbc.gridx;
    p2.add(btnSub, gbc);

    gbc.gridx = 0;
    ++gbc.gridy;
    p2.add(btn7, gbc);
    ++gbc.gridx;
    p2.add(btn8, gbc);
    ++gbc.gridx;
    p2.add(btn9, gbc);
    ++gbc.gridx;
    p2.add(btnMul, gbc);

    gbc.gridx = 0;
    ++gbc.gridy;
    p2.add(btn4, gbc);
    ++gbc.gridx;
    p2.add(btn5, gbc);
    ++gbc.gridx;
    p2.add(btn6, gbc);
    ++gbc.gridx;
    p2.add(btnAdd, gbc);

    gbc.gridx = 0;
    ++gbc.gridy;
    p2.add(btn1, gbc);
    ++gbc.gridx;
    p2.add(btn2, gbc);
    ++gbc.gridx;
    p2.add(btn3, gbc);
    ++gbc.gridx;
    gbc.gridheight = 2; // <- stretch over two rows
    p2.add(btnEq, gbc);

    gbc.gridx = 0;
    ++gbc.gridy;
    gbc.gridheight = 1; // <- reset vertical stretch
    p2.add(btn0, gbc);
    ++gbc.gridx;
    p2.add(btndash, gbc);
    ++gbc.gridx;
    p2.add(btndot, gbc);

    Disclaimer: GridBagLayout is not well-liked and most people prefer third-party layout managers like MigLayout. This sample code uses GridBagLayout because it comes with the JDK and does not require additional libraries.