SWT(JFace)体验之模拟BorderLayout布局

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我是靠谱客的博主愤怒向日葵，最近开发中收集的这篇文章主要介绍SWT(JFace)体验之模拟BorderLayout布局，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

SWT中没有AWT的BorderLayout布局管理器。下面是SWT下的自定义实现：
BorderLayout.java

复制代码代码如下:

package swt_jface.demo2; 
import org.eclipse.swt.SWT; 
import org.eclipse.swt.graphics.Point; 
import org.eclipse.swt.graphics.Rectangle; 
import org.eclipse.swt.widgets.Composite; 
import org.eclipse.swt.widgets.Control; 
import org.eclipse.swt.widgets.Layout; 
public class BorderLayout extends Layout { 
public static final int NORTH = 0; 
public static final int SOUTH = 1; 
public static final int CENTER = 2; 
public static final int EAST = 3; 
public static final int WEST = 4; 
public static class BorderData { 

public int region = CENTER; 
public BorderData() { 
} 
public BorderData(int region) { 
this.region = region; 
} 
} 
public Control[] controls = new Control[5]; 
Point[] sizes; 
int width; 
int height; 
protected Point computeSize(Composite composite, int wHint, int hHint, boolean flushCache) { 

if (sizes == null || flushCache == true) 
refreshSizes(composite.getChildren()); 
int w = wHint; 
int h = hHint; 
if (w == SWT.DEFAULT) w = width; 
if (h == SWT.DEFAULT) h = height; 
return new Point(w, h); 
} 
protected void layout(Composite composite, boolean flushCache) { 
if (flushCache || sizes == null) 
refreshSizes(composite.getChildren()); 
Rectangle clientArea = composite.getClientArea(); 
if (controls[NORTH] != null) { 
controls[NORTH].setBounds( 
clientArea.x, 
clientArea.y, 
clientArea.width, 
sizes[NORTH].y); 
} 
if (controls[SOUTH] != null) { 
controls[SOUTH].setBounds( 
clientArea.x, 
clientArea.y + clientArea.height - sizes[SOUTH].y, 
clientArea.width, 
sizes[SOUTH].y); 
} 
if (controls[WEST] != null) { 
controls[WEST].setBounds( 
clientArea.x, 
clientArea.y + sizes[NORTH].y, 
sizes[WEST].x, 
clientArea.height - sizes[NORTH].y - sizes[SOUTH].y); 
} 
if (controls[EAST] != null) { 
controls[EAST].setBounds( 
clientArea.x + clientArea.width - sizes[EAST].x, 
clientArea.y + sizes[NORTH].y, 
sizes[EAST].x, 
clientArea.height - sizes[NORTH].y - sizes[SOUTH].y); 
} 
if (controls[CENTER] != null) { 
controls[CENTER].setBounds( 
clientArea.x + sizes[WEST].x, 
clientArea.y + sizes[NORTH].y, 
clientArea.width - sizes[WEST].x - sizes[EAST].x, 
clientArea.height - sizes[NORTH].y - sizes[SOUTH].y); 
} 
} 
private void refreshSizes(Control[] children) { 

for (int i = 0; i < children.length; i++) { 
Object layoutData = children[i].getLayoutData(); 
if (layoutData == null || (!(layoutData instanceof BorderData))) 
continue; 
BorderData borderData = (BorderData) layoutData; 
if (borderData.region < 0 || borderData.region > 4) // Invalid. 
continue; 
controls[borderData.region] = children[i]; 
} 
width = 0; 
height = 0; 
if (sizes == null) 
sizes = new Point[5]; 
for (int i = 0; i < controls.length; i++) { 
Control control = controls[i]; 
if (control == null) { 
sizes[i] = new Point(0, 0); 
} else { 
sizes[i] = control.computeSize(SWT.DEFAULT, SWT.DEFAULT, true); 
} 
} 
width = Math.max(width, sizes[NORTH].x); 
width = Math.max(width, sizes[WEST].x + sizes[CENTER].x + sizes[EAST].x); 
width = Math.max(width, sizes[SOUTH].x); 
height = Math.max(Math.max(sizes[WEST].y, sizes[EAST].y), sizes[CENTER].y) 
+ sizes[NORTH].y 
+ sizes[SOUTH].y; 
} 
}

测试代码：
BorderLayoutSample.java

复制代码代码如下:

package swt_jface.demo2; 
import org.eclipse.swt.SWT; 
import org.eclipse.swt.widgets.Button; 
import org.eclipse.swt.widgets.Display; 
import org.eclipse.swt.widgets.Shell; 
import org.eclipse.swt.widgets.Text; 
public class BorderLayoutSample { 

Display display = new Display(); 
Shell shell = new Shell(display); 
public BorderLayoutSample() { 

shell.setLayout(new BorderLayout()); 

Button buttonWest = new Button(shell, SWT.PUSH); 
buttonWest.setText("West"); 
buttonWest.setLayoutData(new BorderLayout.BorderData(BorderLayout.WEST)); 

Button buttonEast = new Button(shell, SWT.PUSH); 
buttonEast.setText("East"); 
buttonEast.setLayoutData(new BorderLayout.BorderData(BorderLayout.EAST)); 
Button buttonNorth = new Button(shell, SWT.PUSH); 
buttonNorth.setText("North"); 
buttonNorth.setLayoutData(new BorderLayout.BorderData(BorderLayout.NORTH)); 

Button buttonSouth = new Button(shell, SWT.PUSH); 
buttonSouth.setText("South"); 
buttonSouth.setLayoutData(new BorderLayout.BorderData(BorderLayout.SOUTH)); 

Text text = new Text(shell, SWT.MULTI | SWT.BORDER | SWT.V_SCROLL | SWT.H_SCROLL); 
text.setText("Center"); 
text.setLayoutData(new BorderLayout.BorderData(BorderLayout.CENTER)); 

shell.pack(); 
shell.open(); 

while (!shell.isDisposed()) { 
if (!display.readAndDispatch()) { 
display.sleep(); 
} 
} 
display.dispose(); 
} 
public static void main(String[] args) { 
new BorderLayoutSample(); 
} 
}