Move a JLabel inside of JPanel without losing hierarchy - java

So I'm moving a JLabel inside of JPanel and I want the JPanel to automatically show scrolls bars that lead you to the JLabel wich I moved out of it.
The problem is that when I set the new JLabel location and this location is out of the JPanel, it loses its hierarchy so the JLabel stops being part of the JPanel and as a result the panel doesn't scrolls and you can't see the JLabel. So this is my code if you can tell how can I do this. Thanks.
//Panel creation
JPanel panel = new JPanel();
panel.setSize(500, 500);
panel.setAutoscrolls(true);
//Label creation
JLabel label = new JLabel();
label.setText("Hi");
label.setSize(40, 40);
//Adding Jlabel to Panel
panel.add(label);
label.setLocation(800, 200);//this invalidates inherancy

What you need to do it encapsulate the JPanel inside a JScrollPane and increase its size with setPreferredSize()
Note that using setSize() setWidth() or setHeight() will be ignored by the scroll pane
A example code of how to set it up follows:
public class TestFrame extends JFrame {
public TestFrame() {
setLayout(null);
setSize(500, 500);
JPanel panel = new JPanel();
panel.setBackground(Color.BLUE);
JScrollPane scroll = new JScrollPane();
scroll.setViewportView(panel);
add(scroll);
scroll.setBounds(100, 100, 200, 200);
panel.setPreferredSize(new Dimension(800, 800));
}
public static void main(String[] args) {
TestFrame frame = new TestFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
In this example, the JScrollPane is fixed with 200x200 size, while the JPanel inside it has a size of 800x800. You can change this value dynamically as you move your JLabel around.
Also, I'd like to mention that null layouts is not the correct approach. In this example, I wanted to minimize the influence of LayoutManagers and underlying calls to setBounds() by them to emphasize the point I'm trying to get across, which is a pure change of size inside a JScrollPane. The whole JFrame is just a "vessel" for the example.

Related

Why does Java pack does not size frame properly when textarea is used with other components?

I am creating a GUI using GridLayout to arrange multiple panels that are using FlowLayout. I am using pack to determine the size of the frame. If I have only a TextArea then it sizes correctly. If I have only other components it sizes correctly. But if I use both p1 and p2 in the code below the panel with the buttons does not size properly. The test code I am using is below. If I use only p1 or p2 it sizes properly, but not with both: Here is the image I am getting. I don't want all that extra space between the buttons and the textarea.
If I do textarea alone it sizes properly.:
public class GUIPractice extends JFrame
{
//declare GUI objects
JPanel panel;
JPanel p1, p2;
JButton btnAdd, btnShow;
JScrollPane js;
JTextArea taOutput;
//constructor
public GUIPractice()
{
//give frame a title
setTitle("GUI Practice");
panel =new JPanel(new GridLayout(0, 1));
btnAdd = new JButton("Add");
btnShow = new JButton("Show");
taOutput = new JTextArea(10, 20);
js = new JScrollPane(taOutput, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
p1 = new JPanel();
p1.add(btnAdd);
p1.add(btnShow);
p2 = new JPanel();
p2.add(js);
panel.add(p1);
panel.add(p2);
//add the panel to the frame
add(panel);
}
public static void main(String[] args)
{
GUIPractice frame = new GUIPractice();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
}
It sizes correctly. The GridLayout means that all cells will be the same size. Since the text area is bigger than the buttons, you see extra space in the panel containing the buttons.
I would suggest you just use the default BorderLayout of the frame.
There is no need for your "panel" using the GridLayout.
You just use:
add(p1, BorderLayout.PAGE_START);
add(p2, BorderLayout.CENTER);
Now the p1 and p2 will be the proper height.
Also, there really is no need for "p2". You can just add the scroll pane directly to the frame.

Trying to add ScrollPane in Jpanel with null layout inside BorderLayout

I am trying to add a scrollbar in jpanel with null layout.
I want to create a form. This should should display few buttons at the bottom at all times.Any content inside form should maintain it's size and ratio even if the parent container is resized.
Here is what I've come with. I have a panel with borderlayout and added buttons at the south of border. Then created another jpanel to contain form that is added at the center of parent jpanel. Since I want form to maintain it's ratio I went with null layout for inner panel. But I want it to display scrollbar when content is not fully visible. enter image description here
Now adding inner jpanel into scrollpane and adding scrollpanel into parent panel (.add(scrollpane, BorderLayout.CENTER)) doesn't give desired format.
Is there any thing that I can do to get desired format?
Here is code Sample:
public static void main(String[] args) {
JFrame jFrame = new JFrame();
jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jFrame.setSize(new Dimension(1000, 700));
Container c = jFrame.getContentPane();
c.setLayout(new BorderLayout());
bottomPanel(c);
centerPanel(c); //scrollbar should go in this panel
jFrame.setVisible(true);
}
private static void centerPanel(Container c) {
JPanel centerPanel = new JPanel();
centerPanel.setLayout(null);
JButton button = new JButton("This jObject should not resize when window resizes and also should maintain relative position.");
button.setBounds(new Rectangle(10, 10, 600, 50));
JButton button1 = new JButton("Just like it works in this code. Just Add ScrollPane to centerPanel That is in green backround");
button1.setBounds(new Rectangle(10, 70, 600, 50));
JButton button2 = new JButton("For clearity");
button2.setBounds(new Rectangle(10, 130, 600, 50));
centerPanel.add(button);
centerPanel.add(button1);
centerPanel.add(button2);
centerPanel.setBackground(Color.GREEN);
c.add(centerPanel, BorderLayout.CENTER);
}
private static void bottomPanel(Container c) {
JPanel bottomPanel = new JPanel(); //Buttons that goes at the bottom of screen will go in here
JPanel bottomInnerPanel = new JPanel();
bottomInnerPanel.setLayout(new BorderLayout());
bottomPanel.setLayout(new GridLayout());
bottomInnerPanel.add(new JButton("Add"), BorderLayout.WEST);
bottomInnerPanel.add(new JButton("Search"), BorderLayout.EAST);
bottomPanel.add(bottomInnerPanel);
bottomPanel.setBorder(BorderFactory.createLineBorder(Color.BLACK));
c.add(bottomPanel, BorderLayout.SOUTH);
}

Swing GUI problems with BorderLayout

I'm currently trying to get along with Layouts, considering that I never really understood them and only did nullLayout instead, absolutely positioning all elements then.
However, I currently have a suitable small project, where I am trying to learn it, which is some small chat service.
Here is a picture right now:
And here is a picture, of how I imagine it to be finished (Please note that this is just some concept, but it should give you the right idea. I'm not a graphic artist):
Here is my current code:
public class Gui {
JFrame frame;
JTextArea textfield;
JTextField enterMessage;
public Gui(){
frame = new JFrame();
frame.setSize(600, 400);
textfield = new JTextArea();
textfield.setText("Textfield");
textfield.setSize(400, 300);
JPanel messagePanel = new JPanel();
JTextField chatMessage = new JTextField();
chatMessage.setText("Send me");
JButton send = new JButton();
send.setText("Send");
messagePanel.add(chatMessage, BorderLayout.WEST);
messagePanel.add(send, BorderLayout.EAST);
frame.add(textfield, BorderLayout.WEST);
frame.add(messagePanel, BorderLayout.SOUTH);
frame.setVisible(true);
}
}
My idea, together with the understanding of BorderLayouts so far was to put the Textfield, where the chat dialog ends up in later on, right inside the frame, on the WEST-side.
The button to send and the field to enter some text will be inside a panel, with an own borderlayout, while the button has some smaller part on the right and the rest of the width is being filled with the textfield.
The whole panel then ends on the SOUTH-side of the frame.
However, right now I have the problem, that the elements keep shrinking to the least possible size.
I tried to fix this with setSize(); , but that does not have an impact at all, it is just being completely ignored.
Any help to point me into the right direction?
Initially, you've got one simple problem:
// should be new JPanel(new BorderLayout())
JPanel messagePanel = new JPanel();
Then, after that, generally BorderLayout likes to stretch the component in BorderLayout.CENTER. So you want to put your textfield and chatMessage in the center.
public Gui(){
frame = new JFrame();
frame.setSize(600, 400);
textfield = new JTextArea();
textfield.setText("Textfield");
// textfield.setSize(400, 300);
JPanel messagePanel = new JPanel(new BorderLayout());
JTextField chatMessage = new JTextField("Send me");
JButton send = new JButton("Send");
messagePanel.add(chatMessage, BorderLayout.CENTER);
messagePanel.add(send, BorderLayout.EAST);
frame.add(textfield, BorderLayout.CENTER);
frame.add(messagePanel, BorderLayout.SOUTH);
frame.setVisible(true);
}
Once you do that, you should get something like this:
But, as a few words of advice:
Don't rely on setSize of a JFrame. Instead, you should use setPreferredSize on a single component which the entire UI should size itself around. (Probably the main text area.) The size of a JFrame includes, for example, the title bar.
You should consider wrapping your JTextArea in a scroll pane. You can then instead setPreferredSize on the viewport.
After you have a component with a preferred size, call pack() on the JFrame before calling setVisible(true). This will size it automatically.
Something like:
frame = new JFrame();
// frame.setSize(600, 400);
...
JScrollPane pane = new JScrollPane(
textfield,
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
// specifying initial size for the
// visible portion of the scroll pane
pane.getViewport().setPreferredSize(new Dimension(320, 200));
frame.add(pane, BorderLayout.CENTER);
frame.add(messagePanel, BorderLayout.SOUTH);
// entire UI sizes around the scroll pane view
frame.pack();
frame.setVisible(true);
Try BoxLayout insted BorderLayout in messagePanel:
messagePanel.setLayout(new BoxLayout(messagePanel,BoxLayout.LINE_AXIS));
messagePanel.add(chatMessage);
messagePanel.add(send);
And for textField:
frame.add(textfield, BorderLayout.CENTER);
Try setting preferred size dimensions of the elements.
textfield.setText("Textfield");
textfield.setPreferredSize(new Dimension(600, 300));
//some other code
JTextField chatMessage = new JTextField();
chatMessage.setPreferredSize(new Dimension(500, 25));
//some other code
As pointed out by Sridhar, BorderLayout does not always respect the dimensions of sub-panels. To fix this, you should initialize your sub-panels (in this case textfield and messagePanel) using setPreferedSize() instead of setSize().
change your constructor to
public Gui() {
frame = new JFrame();
frame.setSize(600, 400);
textfield = new JTextArea();
textfield.setText("Textfield");
textfield.setSize(400, 300);
// set border layout to JPanel
JPanel messagePanel = new JPanel(new BorderLayout());
JTextField chatMessage = new JTextField();
chatMessage.setText("Send me");
JButton send = new JButton();
send.setText("Send");
// add JTextField to CENTER and button to EAST
messagePanel.add(chatMessage, BorderLayout.CENTER);
messagePanel.add(send, BorderLayout.EAST);
// add textArea to CENTER of JFrame
frame.add(textfield, BorderLayout.CENTER);
frame.add(messagePanel, BorderLayout.SOUTH);
frame.setVisible(true);
}
and it will work..

how can i set the size of two JPanel in one JFrame?

how can i modify the size of the panel in the JFrame
am doing a calculator, the first panel will hold the JTextField which i suppose to be small
the second panel will hold the JButtons which suppose to be bigger
JFrame frame = new JFrame(new GridLayout(2, 1));
JPanel panel1 = new JPanel();
JPanel panel2 = new JPabel();
frame.add(panel1);
frame.add(panel2);
i've been trying to make panel1 smaller than panel2 yet nothing worked!
GridLayout would not be an appropriate choice in this scenario since it ignores the preferred sizes of the components inside the container and displays them all at an equal size instead.
I'd suggest using a BorderLayout. You can find a demonstration and description of that layout manager as well as a few others in Oracle's tutorial, A Visual Guide to Layout Managers.
Here's another example using BorderLayout which might be more relevant to your problem.
import java.awt.*;
import javax.swing.*;
public class Test {
public static void main(String []args){
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame();
JPanel panel1 = new JPanel();
JPanel panel2 = new JPanel();
panel1.setBorder(BorderFactory.createTitledBorder("Panel 1"));
panel2.setBorder(BorderFactory.createTitledBorder("Panel 2"));
frame.add(panel1, BorderLayout.NORTH);
frame.add(panel2, BorderLayout.CENTER);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(new Dimension(200, 200));
frame.setVisible(true);
}
});
}
}
Edit: The JFrame's content pane uses a BorderLayout by default, hence the absence of a call to setLayout. Source

Custom JPanel objects overlap when added to JFrame

I'm trying to create a custom timer that will record cumulative time passage separated by days. I have a custom JPanel that does all of the timer work for me. I would like to have a GUI interace with this JPanel represented 7 times. However, when I add more than one custom JPanel to either a JPanel or a JFrame, they don't show up. I've tried setting the layout and setting them to everything I can think of, but nothing works.
This is the basic setup of the Panel:
public class TimerPane extends JPanel{
private static JButton button = new JButton("Start");
private static JLabel label = new JLabel("Time elapsed:");
private static JLabel tLabel = new JLabel("0:0:0");
private static JLabel title = new JLabel("Timer");
public TimerPane(){
button.addActionListener(new ButtonListener());
this.add(title);
this.add(label);
this.add(tLabel);
this.add(button);
this.setOpaque(false);
this.setPreferredSize(new Dimension(100,100));
this.setMaximumSize(new Dimension(100,100));
}
}
This is my latest attempt at getting the JPanel to display multiple times (just twice here):
public static void main(String[] args){
JFrame frame = new JFrame("Timer");
JPanel panel = new JPanel();
frame.setPreferredSize(new Dimension(700,110));
panel.setLayout(new BorderLayout());
panel.add(new TimerPane(), BorderLayout.EAST);
panel.add(new TimerPane(), BorderLayout.WEST);
frame.getContentPane().add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
The GUI that executes after this is 700x110 of which only 100x100 on the far left is used for exactly one of my TimerPane panels. I have also tried GridLayout on the same code, but then only the TimerPane in the second "spot" shows up. Any suggestions?
First of all, please remove the static from the member variables: button, label, tLabel and title. Otherwise, having them static, it means they are shared by all the TimerPane instances.
You will see 2 timer panels now.
Next, you can change the BorderLayout to a FlowLayout for instance and add several instances of TimerPane.
panel.setLayout(new FlowLayout(FlowLayout.LEFT));
panel.add(new TimerPane());
panel.add(new TimerPane());

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