I'm reasonably new to java GUIs and have been using netbeans to help me out.
I've set up a jButton such that when clicked its label changes. My issue is that the size of the button refuses to remain fixed despite setting a maximum and minimum size as well as the setting the preferredSize method. Do I need to change my layout? Should I go through and place each button on a panel or is there a simpler way?
I feel like this should be an easy problem to fix yet I've been at it for over an hour now. I'd appreciate any ideas. Thanks
If you are new to Swing don't use a GUI builder as you will run into all sorts of issues like this one.
It sounds like your Layout is preventing resizing. Make sure you are using the correct Layout Manager for your designed look. Double check any constraints that you have set for the layout. You could experiment with a different layout manager like FlowLayout to check to make sure your setPreferredSize () calls are working correctly etc.
There are a number of ways to handle this:
A clean and easy way would be to create image icons for the different buttons, making them the same size. This lets you completely control what they will look like.
A quick-and-dirty way to do this is the add spaces until the buttons are approximately the same size. This won't be perfect because the fonts that appear on JButons are typically not fixed-width.
The 'proper' Swing way would be to use a custom Layout. For instance, if you use a GridBagLayout to arrange your components, and set the 'weightx' and 'weighty' for the JButton to 1.0, then it will take up as much space as possible, which will keep it the same size.
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I am a self-taught java developer and I use IntelliJ IDEA for Java. Recently I saw a video on youtube in which the guy was using NetBeans and in his JFrame form, he was able to freely place his objects like JButton, JTextFeild, JLabel, etc. I am not able to figure out how to do that. In IntelliJ IDEA I found several layout managers such as Border, Card, Grid, Bag, etc. but none of them gave the desired result. can somebody please tell me how can I get a layout manager in which I can freely place all my objects and also freely resize them without any restrictions? Thank you in advance for any help.
In swing every component extends Container. That means that every component can have nested components (they all have add(Component) method). However, not all of them support the layout-ing of nested components.
What I want to say is, that you can add a component to a JButton, but a JButton is not capable of showing its nested components.
So, in order to have nesting, we use the components - containers that support the orientation of their nested components.
These components are all windows (JFrame, JDialog, etc...) and JPanels. There some others that support layout-ing a specific type of nested components. For example a JMenu is capable of showing JMenuItems properly.
Now, these "top-level"/empty containers are using Layout Managers in order to align-show their nested components. Based on the container's layout manager, the components are shown.
This is why you can't "freely" place the components into a JFrame. Because its Layout Manager is taking care of the components will be placed. So, what you are looking for, is to change its LayoutManager (use setLayout method) to one that allows you to freely place the components.
Guess what? There is no such layout manager. Simply because, it would have nothing to do/calculate since you are taking care the layout of the components. So, in order to achieve the "free" component layout, you must use jframe.setLayout(null);. In order to layout the components after it, you will have to use componentInsideJFrame.setBounds(...) and give it constant coordinates /dimension.
This is bad practice. A very bad one when it comes to UI. Giving a component static coordinates and dimension is bad. There are some questions you have to ask yourself.
What if user resizes the window? If the window is 301x301, the center of it, is at (150,150). So you place a component at (150,150). Ok it works. Now user resizes the window and makes it 501x501. The center is now standing at (250,250). But the component is staying at (150,150). There is the solution of setResizable(false), to this kind of problems, but how often have you used "uncapable of resizing" applications? What if user wants to resize it?
I hope you get it and understood what I am trying to say.
By using layout managers, you are solving this kind of problems easily, since the layout manager will take care of the resize and calculate the new center.
Yes. I know it feels weird, but all these youtube tutorials are not teaching you the correct way to make Swing GUIs. (This is a conversation for another day, I guess)
I truly suggest you read the tutorials of Swing documentation in order to get some ideas of how layout managers work. You will really benefit from those.
Finally, I suggest you to leave outside the whole "gui-builder-tool" thing. They seem to help you building your GUI, but they are adding so much additional/useless code and most of the times they are "bad UI creation" prone. Try to code the GUI by yourself.
At first, this sounds a bit harsh, but you can always run your application and see the result of the GUI. After some mistakes, you will finally be able to imagine the GUI result by only seeing the container.setLayout(..) and container.add(...) lines.
Before I start, I'm aware that its a bad idea to not use a Layout Manager and usually I do use one, however, I also have all my components automatically re-size and relocate based on the size of the window. In addition the program I'm working on is only intended to run on 1 machine throughout its entire lifetime. Please don't downvote me just because of lack of layout manager, I found it to be what I need for this particular program.
To my issue, I found a similar post on stackoverflow but a solution was never achieved.
I'm adding a dynamic amount of JLabels to my JPanel, I've noticed that when not using a layout manager, the scroller doesn't work.
This is a simplified version of my initialization code.
JPanel mypanel = new JPanel();
mypanel.setLayout(null);
mypanel.setSize(800,450);
mypanel.setForeground(Color.WHITE);
mypanel.setBackground(Color.BLACK);
scrollablePanel = new JScrollPane(mypanel);
scrollablePanel.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
scrollablePanel.setPreferredSize(new Dimension(800,300));
scrollablePanel.setSize(800,300);
scrollablePanel.setLocation(250,156);
myContainer.add(scrollablePanel);
where myContainer would be the container (also without a layout manager). The JLabels are added later on to the JPanel with:
enter code heremypanel.add(label1);
after some basic settings are set for the labels such as setForeground and setBackground.
Unfortunately when run, the scrollbar appears as if its not required (see image)
http://i.imgur.com/zp0QKGG.png
The table text seen in the image is made up of multiple JLabels.
If it's not possible to resolve the issue without using a Layout Manager I will switch to BoxLayout, I was just hoping there would be a solution.
The problem is JScrollPanel needs the preferred size of the view component to determine when the view exceeds the scroll pane's viewable area.
The preferred size of a component is normally determined via the layout manager. While you can use setPreferredSize, it is typically discouraged and you will simply run into the same problem as the content exceeds what ever value you decide to set.
A better solution would be to use a LayoutManager or compound layout (using multiple layout managers over multiple containers) to achieve the result you desired...or write your own...
I am trying to create a GUI for a program with an undefined number of rows but stay with two columns. Currently the only way I can get it to look how I want is using FlowLayout but the window of course needs to be smaller than desired. It needs to happen within one panel as well because it is being added to a tabbed pane.
What would be the best layout manager to solve the problem that is in the JDK? Or would just kind of brute forcing it with AbsoluteLayout be the best approach (as the user shouldn't really be resizing the window)?
I have attached the desired appearance.
Thanks for any help in advance.
Several layouts can do what you want. I'd suggest GridLayout (easy to use, but columns will be equal width) or GridBagLayout (harder to use, but you have lots of control). You could also use a BorderLayout and put all the fields in a sub-panel on the WEST and all the drop-downs in a sub-panel on the EAST. The difficulty with that is ensuring that the rows have the same height, since they won't be constrained by the layout itself.
The best thing to do would be to go through the Java tutorial on layouts and get up to speed on what the various layout managers can do.
Also, since you're using Swing, you could just use a JTable (as Gilbert Le Blanc suggests in his comment).
Recently, I started creating a program for the company I work for. Just as background info, I'm still a student and a beginner programmer, so my solution is probably not recommended and I didn't know how to do it otherwise, but it works and I'm not going to be judged for it because it's a student job totally unrelated to programming.
The thing about the program is, it's going to be run on multiple different computer with different screen sizes and resolutions (800x600 and up). To make sure it takes as much of the screen as possible without losing any part of the program, I set the layout to null and hard-coded everything using relative values.
The program is kiosk-style and I first get the screen size values and go from there (for example, off the top of my head, the left-side menu takes an eighth of the screen, the top bar 2%, etc.). I also use font metrics to make sure the components are sized correctly and that everything gets displayed nicely.
My question is: why is it so frowned upon to make the layout null instead of using the layout managers? (I was told on some forums that this is a horrible way of doing things) I know how the layout manager works and know how to use the different layouts, but for the requirements of this program (multiple different resolutions, custom button shapes and placements, text changing on the components when you change language, etc.), I couldn't see myself using the layout managers to do it all.
How do you more experienced programmers use the layout managers in a situation like this? And what do you do when you want a button to be somewhere specific and other components somewhere else specific that don't really match any of the predefined layouts?
If you layer the layout managers correctly the screen will re-flow to different sizes for you, the idea is to use a single set of layout managers on ALL screen sizes.
If you use null you will have to do each screen size yourself. Not only that but if the app can be windowed you have to support every possible size they might scroll to.
That's kind of difficult to do, but the layout mangers are designed to do just that.
There are some common tricks. BorderLayout is a great layout to start with. Sometimes you might use it at multiple levels--often with just 2 or 3 components in it. That's because it's really good at giving all but one area the minimum required area and giving everything else to the CENTER.
FlowLayout can be useful but it's tricky if your components are different sizes.
I wouldn't try GridBagLayout unless you are planning to write code to feed your layout manager (an excellent solution at that!).
I also wouldn't use GUI builders, they don't know the overall way you want to reflow your layout.
In a nutshell: because all the work that you explain above is done (or at least: should be done) by the layout manager.
More often than not, when a null layout is used, it also implies that all positions and sizes are hardcoded to a single value, so no flexibility at all is given. This means that changes in window size, language, font size, display density or any other related parameter have no effect on the layout and you get the usual ugly effects: empty parts of the window; tiny, unresizable lists; buttons with their labels cut off; ...
It sounds like the work you do should really be done by the Layout Manager. Either find one that does that (my personal suggestion would be MiGLayout, which does a lot and is easy to use) or write your own.
You are practically using a layout - your own, with all your sophisticated calculations of positions.
You can move these logic to a custom layout manager class to pacify the critics.
hmmm trick should be by mixing LayoutMangers and by usage of numbers of nested JPanels that each could have diferrent Layout or not, really depends of number of JComponents, that allows you to create GUI that looks like as layed by using AbsoluteLayout but with same look/output to the GUI for every screen resolutions and ratio (4:3, 16:9, 16:10)
I'd like to make a login bar for an application and I can't figure out how to organize a series of JLabels and JTextFields such that they are organized in a horizontal grid without these same components being resized to fit each cell. I also want to make sure that the group of components isn't resized below a certain width. How can this be achieved?
Edit: Thanks for the answers everyone. I'll have a look at MigLayout and SpringLayout later. Due to time constraints I'm going to have to make do with Visual Editor and use a null layout. The component placement and dimensions have to be adjusted by hand but at least they stay put. Here's a picture showing what I wanted to do.
bar http://img145.imageshack.us/img145/7356/bargw.png
Use MigLayout as your layout manager, it's extremely flexible, and supports what you're asking quite easily. You can set size constraints. If you need any further help, post some example code using Swing and MigLayout which shows what you're trying to do, and then I'll advise you on how to do what you want to achieve.
You probably want some additional cells which 'grow' to fill the remaining space. This can be achieved with column constraints, by inserting 'push' between the columns (specified by [..]) to expand the gap. You don't need any placeholder components in this case. (i.e., [pref!]10px[40px::]push[pref!]10px[40px::])
You have to use different layout. FlowLayout or BoxLayout will work in your case, but I would suggest MigLayout simply because it will cover all your needs and replace all others .
Check out the section from the Swing tutorial on Using Layout Managers.
The SpringLayout has an example that does exaclty this.
The GridBagLayout is more difficult to use but also support row/column type layout.
Finally, you can still use a GridLayout. Just add the text fields to a JPanel first, then the panel will grow but the text field won't.