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)
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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.
When creating Swing GUI's, how can I best choose the horizontal and vertical gaps to be used to separate components? Something like asked here Windows Layout Look and Feel, but platform independent.
Generally I simply used 5 pixels for everything, that looked reasonable with the Windows Classic theme, but looks somewhat odd when running under Windows 8, especially when there are multiple nested container components (e.g. Dialog -> TabbedPane -> ScrollPane).
I have looked at UIDefaults, but there doesn't really seems to be any hints about component spacing there (I was hoping to find at least a few values that could be used as hints, but LayoutManagers seem to generally use hardcoded deafults, e.g. FlowLayout uses a hardcoded 5 pixel spacing).
What approaches can I take to make my layouts more look and feel aware (I am generally using the System Look and Feel) ?
If you want a layout of components that change a bit to fit your user's platform, then perhaps just use the user's system look and feel with:
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
Edit to provide solution for specifying more specific gaps.
To specify margin and padding between components you can try using a box layout. You might not need to use a box layout throughout the entire Swing code you have either, perhaps have a utility function you use right before you add a component that accepts a Swing component, and a left right top and bottom margin/padding. This function would then return you a JPanel with a box layout with the margin/padding passed, along with containing one component, the one you passed in.
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).
I'm new to layout managers like Flow, borders, ...
I mostly use setBounds() to set the position of my components.
I read on an article that using setBounds is not an good practice and it's better to use some layout.
Which are the best and most used layouts?
How to position a button using layout managers; instead of doing setbounds(10,10,100,30)?
look here: http://download.oracle.com/javase/tutorial/uiswing/layout/using.html
Basically you should forget about coordinates. Look at your dialogs at a higher level of design. Questions you should ask yourself.
1) Is there a "main" area with smaller surrounding areas in your design. If so use a BorderLayout.
2) Is there equal grid like areas in your design, If so use a GridLayout.
3) If you need a top-down, or left-right layout, consider a BoxLayout
4) If you want to show a complex form, probably use a FormLayout from jgoodies.
But you have to look at things from a high level. There may be subsections in any one top level section of your dialog. If that is the case, then you need to put a JPanel in that section, and then use a sub layout in that JPanel. Use the above questions over again for that panel.
Besides "standard" Swing layouts (part of the JDK), there are many third-party (mostly open source) LayoutManagers that often are much better than Swing ones.
For a comparison of many LayoutManagers on a real example (with code), check out this link, although a bit old, it still shows the various features and ease of use of predominant LayoutManagers nowadays.
In general, I would advise DesignGridLayout which, although quite powerful, is very easy to use (you don't need a GUI designer to use and it's easy to maintain layout code of existing panels); it just takes one hour to understand it.
Also, MigLayout is viewed as the most flexible one (might be useful if you need very complex layouts), but it takes more time to get used to it, and sometimes you have to use "tricks"to make it work as you want.
..which is the best and most used layout (?)
Nested layouts. Use whatever layout works best for different groups of GUI components, then put them in panels inside other panels (with other layouts). See this Nested Layout Example for a demo. of combining layouts.
As to which best individual layouts to use, do the tutorial linked by MBFG to get a feel for what each can achieve, their strengths & weaknesses.
I will commonly use nested combinations of BorderLayout, GridLayout & FlowLayout, with an occasional GridBagLayout.
I have a doubt in layouts.I have designed one layout using group layout using addgaps and groups.My Question is whether my design changes with screen size?That is I have designed layout for 15 inches monitor will the layout looks same in bigger size monitor screen?
Thank u
chaithu
It depends on how you designed the layout. If you assign sizes and positions to components using pixels, then it won't scale. If you made good use of preferredSize and other properties designed to work with dynamic sizes, then it will scale.
Which did you do? You say you used group layouts, which means your screen will most likely scale. How well it scales is another question entirely.
Do you not have the opportunity to try the layout on a larger monitor to see if it works?
If you make the window smaller, does it update the layout to fit components? If yes, then most probably it will look fine on larger screen, if not... anyways, group layout is intended for GUI builders (like NetBeans). For handmade GUI, Box and BorderLayout will do the job most of the time.