Java Tutorial/SWT/Button

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Add Image to Button

To get and set a button"s image label, use the following method



   <source lang="java">

public Image getImage() 

   public void setImage(Image image)</source>



Add Radio Buttons to a Composite to form a group

   <source lang="java">

import org.eclipse.swt.SWT; import org.eclipse.swt.layout.FillLayout; import org.eclipse.swt.layout.RowLayout; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.ruposite; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; public class RadioButtonComposite { 

 public static void main(String[] args) {
   final Display display = new Display();
   final Shell shell = new Shell(display);
   shell.setLayout(new FillLayout());
   Composite composite = new Composite(shell, SWT.NULL);
   composite.setLayout(new RowLayout());
   Button mrButton = new Button(composite, SWT.RADIO);
   mrButton.setText("Mr.");
   Button mrsButton = new Button(composite, SWT.RADIO);
   mrsButton.setText("Mrs.");
   Button msButton = new Button(composite, SWT.RADIO);
   msButton.setText("Ms.");
   Button drButton = new Button(composite, SWT.RADIO);
   drButton.setText("Dr.");
   shell.open();
   // Set up the event loop.
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch()) {
       // If no more entries in event queue
       display.sleep();
     }
   }
   display.dispose();
 }

}</source>





ArrowButton

   <source lang="java">

import org.eclipse.swt.SWT; import org.eclipse.swt.layout.*; import org.eclipse.swt.widgets.*; public class ArrowButtonExample { 

 public static void main(String[] args) {
   Display display = new Display();
   Shell shell = new Shell(display);
   shell.setLayout(new GridLayout(3, true));
   // Create three arrow buttons
   new Button(shell, SWT.ARROW);
   new Button(shell, SWT.ARROW | SWT.LEFT);
   new Button(shell, SWT.ARROW | SWT.DOWN);

   shell.pack();
   shell.open();
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch()) {
       display.sleep();
     }
   }
   display.dispose();
 }

}</source>





CheckBox Button

   <source lang="java">

import org.eclipse.swt.SWT; import org.eclipse.swt.layout.*; import org.eclipse.swt.widgets.*; public class CheckBoxButtonExample { 

 public static void main(String[] args) {
   Display display = new Display();
   Shell shell = new Shell(display);
   shell.setLayout(new GridLayout(3, true));
   // Create three checkboxes
   new Button(shell, SWT.CHECK).setText("Checkbox 1");
   new Button(shell, SWT.CHECK).setText("Checkbox 2");
   new Button(shell, SWT.CHECK).setText("Checkbox 3");
   shell.pack();
   shell.open();
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch()) {
       display.sleep();
     }
   }
   display.dispose();
 }

}</source>





FlatButton

   <source lang="java">

import org.eclipse.swt.SWT; import org.eclipse.swt.layout.*; import org.eclipse.swt.widgets.*; public class FlatButtonExample { 

 public static void main(String[] args) {
   Display display = new Display();
   Shell shell = new Shell(display);
   shell.setLayout(new GridLayout(3, true));
   // Create three flat buttons
   new Button(shell, SWT.FLAT).setText("Flat 1");
   new Button(shell, SWT.FLAT).setText("Flat 2");
   new Button(shell, SWT.FLAT).setText("Flat 3");

   shell.pack();
   shell.open();
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch()) {
       display.sleep();
     }
   }
   display.dispose();
 }

}</source>





Introducing Button and Button Styles

  1. SWT uses Button to represent checkboxes, toggle buttons, and radio buttons.
  2. You determine the type by the style constants.
  3. You may pass only one of SWT.LEFT, SWT.CENTER, or SWT.RIGHT.
  4. You may pass only one of SWT.ARROW, SWT.CHECK, SWT.PUSH, SWT.RADIO, or SWT.TOGGLE.
  5. If you pass SWT.ARROW, you may pass only one of SWT.UP, SWT.DOWN, SWT.LEFT, or SWT.RIGHT.

StyleDescriptionSWT.ARROWCreates a push button that displays an arrow.SWT.CHECKCreates a checkbox.SWT.PUSHCreates a push button.SWT.RADIOCreates a radio button.SWT.TOGGLECreates a push button that preserves its pushed or nonpushed state.SWT.FLATCreates a push button that appears flat.SWT.UPWhen combined with SWT.ARROW, displays an upward-pointing arrow.SWT.DOWNWhen combined with SWT.ARROW, displays a downward-pointing arrow.SWT.CENTERCenters the associated text.SWT.LEFTLeft-aligns the associated text. When combined with SWT.ARROW, displays a leftward-pointing arrow.SWT.RIGHTRight-aligns the associated text. When combined with SWT.ARROW, displays a rightward-pointing arrow.


LEFT, RIGHT, CENTER: These three styles specify the text/image alignment in buttons.

   <source lang="java">

import org.eclipse.swt.SWT; import org.eclipse.swt.layout.FillLayout; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; public class ButtonTextAlignment { 

 public static void main(String[] args) {
   final Display display = new Display();
   final Shell shell = new Shell(display, SWT.SHELL_TRIM);
   shell.setLayout(new FillLayout());
   Button button = new Button(shell, SWT.RIGHT);
   button.setText("text on the button");
   shell.open();
   // Set up the event loop.
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch()) {
       // If no more entries in event queue
       display.sleep();
     }
   }
   display.dispose();
 }

}</source>





Push Button

   <source lang="java">

import org.eclipse.swt.SWT; import org.eclipse.swt.layout.*; import org.eclipse.swt.widgets.*; public class PushButtonExample { 

 public static void main(String[] args) {
   Display display = new Display();
   Shell shell = new Shell(display);
   shell.setLayout(new GridLayout(3, true));
   // Create three push buttons
   new Button(shell, SWT.PUSH).setText("Push 1");
   new Button(shell, SWT.PUSH).setText("Push 2");
   new Button(shell, SWT.PUSH).setText("Push 3");
   shell.pack();
   shell.open();
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch()) {
       display.sleep();
     }
   }
   display.dispose();
 }

}</source>





RadioButton

By default all the radio buttons sharing the same parent belong to the same group.



   <source lang="java">

import org.eclipse.swt.SWT; import org.eclipse.swt.layout.*; import org.eclipse.swt.widgets.*; public class RadioButtonExample { 

 public static void main(String[] args) {
   Display display = new Display();
   Shell shell = new Shell(display);
   shell.setLayout(new GridLayout(3, true));
   // Create three radio buttons
   new Button(shell, SWT.RADIO).setText("Radio 1");
   new Button(shell, SWT.RADIO).setText("Radio 2");
   new Button(shell, SWT.RADIO).setText("Radio 3");

   shell.pack();
   shell.open();
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch()) {
       display.sleep();
     }
   }
   display.dispose();
 }

}</source>





Select a Radio Button

If you need to select a button programmatically, use the following method:



   <source lang="java">

public void setSelection(boolean selected)</source>





Set the alignment of the text/image label of a button

Set the alignment of the text/image label of a button in the constructor of the Button class, or you can use the setAlignment method after it has been created:



   <source lang="java">

public void setAlignment(int alignment)</source>





Setting Button selection

   <source lang="java">

import org.eclipse.swt.SWT; import org.eclipse.swt.layout.FillLayout; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.Control; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; public class ButtonSelection { 

 public static void main(String[] args) {
   Display display = new Display();
   final Shell shell = new Shell(display);
   shell.setLayout(new FillLayout());
   
   for (int i = 0; i < 20; i++) {
     Button button = new Button(shell, SWT.TOGGLE);
     button.setText("B" + i);
   }
   Control[] children = shell.getChildren();
   for (int i = 0; i < children.length; i++) {
     Control child = children[i];
     ((Button) child).setSelection(true);
   }
   shell.pack();
   shell.open();
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch())
       display.sleep();
   }
   display.dispose();
 }

}</source>





To escape the mnemonic character &, you can double it and a single "&" will be displayed.

   <source lang="java">

import org.eclipse.swt.SWT; import org.eclipse.swt.layout.RowLayout; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; public class EscapeMnemonicCharacter { 

 public static void main(String[] args) {
   final Display display = new Display();
   final Shell shell = new Shell(display, SWT.SHELL_TRIM);
   shell.setLayout(new RowLayout());
   Button button = new Button(shell, SWT.RIGHT);
   button.setText("&&text on the button");
   shell.open();
   // Set up the event loop.
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch()) {
       // If no more entries in event queue
       display.sleep();
     }
   }
   display.dispose();
 }

}</source>





To get and set a button"s text label

   <source lang="java">

public String getText() 

   public void setText(String text)</source>



Toggle Button

   <source lang="java">

import org.eclipse.swt.SWT; import org.eclipse.swt.layout.*; import org.eclipse.swt.widgets.*; public class ToggleButtonExample { 

 public static void main(String[] args) {
   Display display = new Display();
   Shell shell = new Shell(display);
   shell.setLayout(new GridLayout(3, true));
   // Create three toggle buttons
   new Button(shell, SWT.TOGGLE).setText("Toggle 1");
   new Button(shell, SWT.TOGGLE).setText("Toggle 2");
   new Button(shell, SWT.TOGGLE).setText("Toggle 3");
   shell.pack();
   shell.open();
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch()) {
       display.sleep();
     }
   }
   display.dispose();
 }

}</source>





You can include the mnemonic character in the text label.

Inserting an ampersand (&) before a character makes the character the mnemonic.



   <source lang="java">

import org.eclipse.swt.SWT; import org.eclipse.swt.layout.RowLayout; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; public class ButtonAmpersandCharacter { 

 public static void main(String[] args) {
   final Display display = new Display();
   final Shell shell = new Shell(display, SWT.SHELL_TRIM);
   shell.setLayout(new RowLayout());
   Button button = new Button(shell, SWT.RIGHT);
   button.setText("&text on the button");
   shell.open();
   // Set up the event loop.
   while (!shell.isDisposed()) {
     if (!display.readAndDispatch()) {
       // If no more entries in event queue
       display.sleep();
     }
   }
   display.dispose();
 }

}</source>



When the user presses a key matching the mnemonic, the corresponding button is selected and a selection event is generated as a result.

Источник — «http://jexp.ru/index.php?title=Java_Tutorial/SWT/Button&oldid=3086»