Example Analysis of layout Controller in javaGUI programming
javaGUI programming layout controller example analysis, I believe that many inexperienced people are helpless, this article summarizes the causes of the problem and solutions, through this article I hope you can solve this problem.
Layout controller is used to automatically assign how each component is arranged inside the window; the default is FlowLayout, i.e. sorting one by one. FlowLayout is Panel
instance 1：FlowLayout
import java.awt.*; public class TestLayout { public static void main(String[] args) { Frame f = new Frame(); Button b1 = new Button("ok"); Button b2 = new Button("open"); Button b3 = new Button("change"); f.setBackground(Color.BLUE); f.setBounds(100, 100, 300, 300); f.setLayout(new FlowLayout()); f.setResizable(true); f.add(b1); f.add(b2); f.add(b3); f.setVisible(true); }}
instance 2：BorderLayout
import java.awt.*; public class TestBorderLayout { public static void main(String[] args) { Frame f = new Frame("Border Layout"); Button bn = new Button("Bn"); Button bs = new Button("Bs"); Button be = new Button("Be"); Button bw = new Button("Bw"); Button bc = new Button("Bc"); // f.add(bw,"West");// f.add(be,"East");// f.add(bn,"North");// f.add(bs,"South");// f.add(bc,"Center");// f.setLayout(new BordorLayout()); f.add(bn,BorderLayout.NORTH); f.add(bs,BorderLayout.SOUTH); f.add(bw,BorderLayout.WEST); f.add(be,BorderLayout.EAST); f.add(bc,BorderLayout.CENTER); f.setSize(200, 200); f.setVisible(true); }}
BorderLayout divides the entire interface into five regional blocks in the east, west, north and south; BorderLayout.NORTH is int type data and is a constant.
instance 3：GridLayout
import java.awt.*; public class TestGridLayout { public static void main(String[] args) { Frame f = new Frame(); Button b1 = new Button("b1"); Button b2 = new Button("b2"); Button b3 = new Button("b3"); Button b4 = new Button("b4"); Button b5 = new Button("b5"); Button b6 = new Button("b6"); f.setLayout(new GridLayout(3,2)); f.add(b1); f.add(b2); f.add(b3); f.add(b4); f.add(b5); f.add(b6); f.pack(); f.setSize(200, 200); f.setVisible(true); }}
Note: When Layout is called, the size and position of its internal components are assigned by the system (Layout Manager), and cannot be considered as a design. The pack() method is used to display components.
instance 4: Integrated instance
import java.awt.*; public class TestedLayout { public static void main(String[] args) { Frame f = new Frame("GUI"); f.setLayout(new GridLayout(2,1)); Panel p1 = new Panel(new BorderLayout()); Panel p2 = new Panel(new BorderLayout()); Panel p11 = new Panel(new GridLayout(2,1)); Panel p22 = new Panel(new GridLayout(2,2)); Button b1 = new Button("button"); Button b2 = new Button("button"); Button b3 = new Button("button"); Button b4 = new Button("button"); Button b5 = new Button("button"); Button b6 = new Button("button"); Button b7 = new Button("button"); Button b8 = new Button("button"); Button b9 = new Button("button"); Button b10 = new Button("button"); p1.add(b1,BorderLayout.WEST); p1.add(b2,BorderLayout.EAST); p2.add(b3,BorderLayout.WEST); p2.add(b4,BorderLayout.EAST); p11.add(b5); p11.add(b6); p22.add(b7); p22.add(b8); p22.add(b9); p22.add(b10); p1.add(p11,BorderLayout.CENTER); p2.add(p22,BorderLayout.CENTER); f.add(p1); f.add(p2); f.setBounds(100, 100, 400, 400); f.setVisible(true); }}
Note: A new creates a button object and allocates a memory space. Even if it is exactly the same button, that is, the same size name, etc., it is still one after all. When it is repeatedly added, it is only equivalent to changing its position. Unlike variables, it is not a simple copy, but a memory and object pointing problem.
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