Motivācija: Būdama platformneatkarīga valoda, Java arī GUI platformu veido platformneatkarīgi. Kā tas notiek?
1 import java.awt.*;
2
3 public class FrameExample {
4 private Frame f;
5
6 public FrameExample() {
7 f = new Frame("Hello Out There!");
8 }
9
10 public void launchFrame() {
11 f.setSize(170,170);
12 f.setBackground(Color.blue);
13 f.setVisible(true);
14 }
15
16 public static void main(String args[]) {
17 FrameExample guiWindow = new FrameExample();
18 guiWindow.launchFrame();
19 }
20 }
1 import java.awt.*;
2
3 public class FrameWithPanel {
4 private Frame f;
5 private Panel pan;
6
7 public FrameWithPanel(String title) {
8 f = new Frame(title);
9 pan = new Panel();
10 }
11
12 public void launchFrame() {
13 f.setSize(200,200);
14 f.setBackground(Color.blue);
15 f.setLayout(null); // atspējo noklusēto izvietotāju
16
17 pan.setSize(100,100);
18 pan.setBackground(Color.yellow);
19 f.add(pan);
20 f.setVisible(true);
21 }
22
23 public static void main(String args[]) {
24 FrameWithPanel guiWindow =
25 new FrameWithPanel("Frame with Panel");
26 guiWindow.launchFrame();
27 }
28 }
1 import java.awt.*;
2
3 public class LayoutExample {
4 private Frame f;
5 private Button b1;
6 private Button b2;
7
8 public LayoutExample() {
9 f = new Frame("GUI example");
10 b1 = new Button("Press Me");
11 b2 = new Button("Don't press Me");
12 }
13
14 public void launchFrame() {
15 f.setLayout(new FlowLayout());
16 f.add(b1);
17 f.add(b2);
18 f.pack();
19 f.setVisible(true);
20 }
21
22 public static void main(String args[]) {
23 LayoutExample guiWindow = new LayoutExample();
24 guiWindow.launchFrame();
25 }
26 }
1 import java.awt.*;
2
3 public class FlowExample {
4 private Frame f;
5 private Button button1;
6 private Button button2;
7 private Button button3;
8
9 public FlowExample() {
10 f = new Frame("Flow Layout");
11 button1 = new Button("Ok");
12 button2 = new Button("Open");
13 button3 = new Button("Close");
14 }
15
16 public void launchFrame() {
17 f.setLayout(new FlowLayout());
18 f.add(button1);
19 f.add(button2);
20 f.add(button3);
21 f.setSize(100,100);
22 f.setVisible(true);
23 }
24
25 public static void main(String args[]) {
26 FlowExample guiWindow = new FlowExample();
27 guiWindow.launchFrame();
28 }
29 }
Noklusētais izvietojums klasei Frame. Komponentus pievieno norādītajiem reģioniem Komponentu uzvedība staipīšanas (resizing) rezultātā:
1 import java.awt.*;
2
3 public class BorderExample {
4 private Frame f;
5 private Button bn, bs, bw, be, bc;
6
7 public BorderExample() {
8 f = new Frame("Border Layout");
9 bn = new Button("B1");
10 bs = new Button("B2");
11 bw = new Button("B3");
12 be = new Button("B4");
13 bc = new Button("B5");
14 }
15
16 public void launchFrame() {
17 f.add(bn, BorderLayout.NORTH);
18 f.add(bs, BorderLayout.SOUTH);
19 f.add(bw, BorderLayout.WEST);
20 f.add(be, BorderLayout.EAST);
21 f.add(bc, BorderLayout.CENTER);
22 f.setSize(200,200);
23 f.setVisible(true);
24 }
25
26 public static void main(String args[]) {
27 BorderExample guiWindow2 = new BorderExample();
28 guiWindow2.launchFrame();
29 }
30 }
1 import java.awt.*;
2
3 public class GridExample {
4 private Frame f;
5 private Button b1, b2, b3, b4, b5, b6;
6
7 public GridExample() {
8 f = new Frame("Grid Example");
9 b1 = new Button("1");
10 b2 = new Button("2");
11 b3 = new Button("3");
12 b4 = new Button("4");
13 b5 = new Button("5");
14 b6 = new Button("6");
15 }
16
17 public void launchFrame() {
18 f.setLayout (new GridLayout(3,2));
19
20 f.add(b1);
21 f.add(b2);
22 f.add(b3);
23 f.add(b4);
24 f.add(b5);
25 f.add(b6);
26
27 f.pack();
28 f.setVisible(true);
29 }
30
31 public static void main(String args[]) {
32 GridExample grid = new GridExample();
33 grid.launchFrame();
34 }
35 }
1 import java.awt.*;
2
3 public class ComplexLayoutExample {
4 private Frame f;
5 private Panel p;
6 private Button bw, bc;
7 private Button bfile, bhelp;
8
9 public ComplexLayoutExample() {
10 f = new Frame("GUI example 3");
11 bw = new Button("West");
12 bc = new Button("Work space region");
13 bfile = new Button("File");
14 bhelp = new Button("Help");
15 }
16
17 public void launchFrame() {
18 // Add bw and bc buttons in the frame border
19 f.add(bw, BorderLayout.WEST);
20 f.add(bc, BorderLayout.CENTER);
21 // Create panel for the buttons in the north border
22 p = new Panel();
23 p.add(bfile);
24 p.add(bhelp);
25 f.add(p, BorderLayout.NORTH);
26 // Pack the frame and make it visible
27 f.pack();
28 f.setVisible(true);
29 }
30
31 public static void main(String args[]) {
32 ComplexLayoutExample gui = new ComplexLayoutExample();
33 gui.launchFrame();
34 }
35 }
Diskusiju tēma: Šajā nodaļā izskaidrots, kā veidot dažādus GUI elementus, un kā tos novietot uz aplikācijas ekrāna. Kas jādara, lai GUI saskarnei būtu laba lietojamība (usability)? Sal. MIT lekcijas par lietojamību - 1.lekcija un 2.lekcija