Press TAB to next Java in Vertical axis component

Question

I have a panel null layout and have the following code

int k=130;
int h=10;
for (int i=0; i<22; ++i) {
    jTextFieldArray[i] = new JTextField();
    jTextFieldArray[i].setBounds(k, h, 120, 25);
    String s = Integer.toString(i+1);
    jTextFieldArray[i].setText(s);
    h+=30;
    panel.add(jTextFieldArray[i]);  
    if (i==10) k=430; 
    if (i==10) h=10;
}

When I press TAB, the cursor will move to the next horizontal Textfield. How can I make it moving or pointing to the next horizontal Textfield

Java GUIs have to work on different OS', screen size, screen resolution etc. As such, they are not conducive to pixel perfect layout. Instead use layout managers, or [combinations of them](http://stackoverflow.com/a/5630271/418556) along with layout padding and borders for [white space](http://stackoverflow.com/a/17874718/418556). *"How can I make it moving or pointing to the next horizontal Textfield"* What? You want focus to move to the next text field when the mouse points to it, or ..what? — Andrew Thompson, Apr 11 '15 at 18:28

score 2 · Answer 1 · answered Apr 11 '15 at 19:34

If my interpretation of the question is correct you would like to customize the focus traversal. You can provide your own focus traversal policy to override default focus cycling order. Take a look at Customizing Focus Traversal topic in How to Use the Focus Subsystem tutorial. It has an example that illustrates how to install a custom policy.

On a side note, as already mentioned in comments, absolute positioning (null layout) has many drawbacks and should be considered with extra care. Null layouts should/can be avoided in most cases. As stated in Doing Without a Layout Manager (Absolute Positioning):

Although it is possible to do without a layout manager, you should use a layout manager if at all possible. A layout manager makes it easier to adjust to look-and-feel-dependent component appearances, to different font sizes, to a container's changing size, and to different locales. Layout managers also can be reused easily by other containers, as well as other programs.

Take a look at A Visual Guide to Layout Managers to get familiar with Swing layouts.

score 0 · Answer 2 · edited May 23 '17 at 10:24

As an example - using the Customizing Focus Traversal topic in How to Use the Focus Subsystem tutorial that was already mentioned by Aqua:

private void tryCustomFocusTraversal() {
    final JFrame frame = new JFrame("Stack Overflow: vertical tab order");
    frame.setBounds(100, 100, 800, 600);
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    final JPanel panel = new JPanel(null);
    final JTextField[] jTextFieldArray = new JTextField[22];

    int k = 130;
    int h = 10;
    for (int i = 0; i < jTextFieldArray.length; ++i) {
        jTextFieldArray[i] = new JTextField();
        jTextFieldArray[i].setBounds(k, h, 120, 25);
        String s = Integer.toString(i + 1);
        jTextFieldArray[i].setText(s);
        h += 30;
        panel.add(jTextFieldArray[i]);
        if (i == 10) k = 430;
        if (i == 10) h = 10;
    }

    frame.getContentPane().add(panel);
    frame.setFocusTraversalPolicy(new CustomFocusTraversalPolicy(Arrays.asList(jTextFieldArray)));
    frame.setVisible(true);
}

Which uses the CustomFocusTraversalPolicy class:

import java.awt.Component;
import java.awt.Container;
import java.awt.FocusTraversalPolicy;
import java.util.ArrayList;
import java.util.List;

public class CustomFocusTraversalPolicy extends FocusTraversalPolicy {
    private final List<Component> componentOrder = new ArrayList<>();

    public CustomFocusTraversalPolicy(final List<Component> componentOrder) {
        this.componentOrder.addAll(componentOrder);
    }

    public Component getComponentAfter(final Container focusCycleRoot, final Component aComponent) {
        return componentOrder.get((componentOrder.indexOf(aComponent) + 1) % componentOrder.size());
    }

    public Component getComponentBefore(final Container focusCycleRoot, final Component aComponent) {
        final int currentIndex = componentOrder.indexOf(aComponent);
        return componentOrder.get(currentIndex > 0 ? currentIndex - 1 : componentOrder.size() - 1);
    }

    public Component getFirstComponent(final Container focusCycleRoot) {
        return componentOrder.get(0);
    }

    public Component getLastComponent(final Container focusCycleRoot) {
        return componentOrder.get(componentOrder.size() - 1);
    }

    public Component getDefaultComponent(final Container focusCycleRoot) {
        return getFirstComponent(focusCycleRoot);
    }
}

Press TAB to next Java in Vertical axis component

2 Answers2

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