SWT(JFace)体验之GridLayout布局

2009-06-25 11:18:06 作者：

GridLayout 布局的功能非常强大，也是笔者常用的一种布局方式。GridLayout是网格式布局，它把父组件分成一个表格，默认情况下每个子组件占据一个单元格的空间，每个子组件按添加到父组件的顺序排列在表格中。

GridLayout布局

GridLayout 布局的功能非常强大，也是笔者常用的一种布局方式。GridLayout是网格式布局，它把父组件分成一个表格，默认情况下每个子组件占据一个单元格的空间，每个子组件按添加到父组件的顺序排列在表格中。GridLayout提供了很多的属性，可以灵活设置网格的信息。另外，GridLayout 布局提供了GridData类，子组件可以设置相应的GridData，例如 “dogPhoto.setLayoutData(gridData)”，GridData可以设置每个组件当做单元格的信息。

GridLayout的风格

GridLayout类提供了GridLayout 布局中划分网格的信息，主要通过以下几个参数进行设置。

NumColumns：通过“gridLayout.numColumns”属性可以设置父组件中分几列显示子组件。

MakeColumnsEqualWidth：通过“gridLayout. makeColumnsEqualWidth”属性可以设置父组件中子组件是否有相同的列宽，当MakeColumnsEqualWidth为true时表示每列的列宽相等。
MarginLeft：表示当前组件距离父组件左边距的像素点个数。
MarginRight：表示当前组件距离父组件右边距的像素点个数。
MarginTop：表示当前组件距离父组件上边距的像素点个数。
MarginBottom：表示当前组件距离父组件下边距的像素点个数。
HorizontalSpacing：表示子组件的水平间距。
VerticalSpacing：表示子组件的垂直间距。

GridData的相关属性

GridLayout布局的灵活之处在于它利用网格布局数据GridData。通过GridData可以设置子组件在网格中的填充方式、大小边距等信息，用户可以通过子组件的setLayoutData方法设置网格布局数据。

GridData可以控制子组件在网格中的位置大小等相关显示信息。GridData可以设置如下的一些属性。

HorizontalAlignment：表示水平对齐方式。

VerticalAlignment：表示子组件的垂直对齐方式，值和水平方式一样。
HorizontalIndent：表示子组件水平偏移多少像素。此属性和“horizontalAlignment = GridData.BEGINNING”属性一起使用。

HorizontalSpan：表示组件水平占据几个网格。

GrabExcessHorizontalSpace：表示当父组件大小改变时，子组件是否以水平方向抢占空间。
GrabExcessVerticalSpace：表示当父组件大小改变时，子组件是否以垂直方向抢占空间。
WidthHint：表示子组件的宽度为多少像素（前提是未设置其他相关属性）。
HeightHint：表示子组件的高度为多少像素（前提是未设置其他相关属性）。

另外，GridData可以通过构造函数指定相应的属性值，有兴趣的读者可以参考GridData类的构造函数。

测试代码:

GridLayoutSample.java

复制代码代码如下:

package swt_jface.demo2; 
import org.eclipse.swt.SWT; 
import org.eclipse.swt.layout.GridData; 
import org.eclipse.swt.layout.GridLayout; 
import org.eclipse.swt.widgets.Button; 
import org.eclipse.swt.widgets.Display; 
import org.eclipse.swt.widgets.List; 
import org.eclipse.swt.widgets.Shell; 
public class GridLayoutSample { 

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

GridLayout gridLayout = new GridLayout(); 
gridLayout.numColumns = 2; 
gridLayout.makeColumnsEqualWidth = true; 
shell.setLayout(gridLayout); 
Button button1 = new Button(shell, SWT.PUSH); 
button1.setText("button1"); 
button1.setLayoutData(new GridData(GridData.VERTICAL_ALIGN_BEGINNING)); 

List list = new List(shell, SWT.BORDER); 
list.add("item 1"); 
list.add("item 2"); 
list.add("item 3"); 
list.setLayoutData(new GridData(GridData.VERTICAL_ALIGN_CENTER)); 

Button button2 = new Button(shell, SWT.PUSH); 
button2.setText("button #2"); 
GridData gridData = new GridData(GridData.VERTICAL_ALIGN_END); 
gridData.horizontalIndent = 5; 
button2.setLayoutData(gridData); 

Button button3 = new Button(shell, SWT.PUSH); 
button3.setText("3"); 
button3.setLayoutData(new GridData(GridData.VERTICAL_ALIGN_FILL)); 

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

GridLayoutSampleGrabSpace.java

复制代码代码如下:

package swt_jface.demo2; 
import org.eclipse.swt.SWT; 
import org.eclipse.swt.layout.GridData; 
import org.eclipse.swt.layout.GridLayout; 
import org.eclipse.swt.widgets.Button; 
import org.eclipse.swt.widgets.Display; 
import org.eclipse.swt.widgets.Label; 
import org.eclipse.swt.widgets.Shell; 
import org.eclipse.swt.widgets.Text; 
public class GridLayoutSampleGrabSpace { 
public GridLayoutSampleGrabSpace() { 

Display display = new Display(); 
Shell shell = new Shell(display); 

GridLayout gridLayout = new GridLayout(); 
gridLayout.numColumns = 3; 
shell.setLayout(gridLayout); 

Label label = new Label(shell, SWT.BORDER); 
label.setText("label"); 

GridData gridData3 = new GridData(); 
gridData3.widthHint = 60; 
gridData3.heightHint = 20; 

label.setLayoutData(gridData3); 

Text text = new Text(shell, SWT.SINGLE | SWT.BORDER); 
text.setText("text"); 

GridData gridData = new GridData(); 
gridData.grabExcessHorizontalSpace = true; 
gridData.grabExcessVerticalSpace = true; 
gridData.horizontalAlignment = GridData.FILL; 
gridData.verticalAlignment = GridData.FILL; 
text.setLayoutData(gridData); 

Button button = new Button(shell, SWT.PUSH); 
button.setText("button"); 

GridData gridData2 = new GridData(); 
gridData2.grabExcessVerticalSpace = true; 
gridData2.grabExcessHorizontalSpace = true; 
gridData2.verticalAlignment = GridData.FILL; 
gridData2.horizontalAlignment = GridData.FILL; 

button.setLayoutData(gridData2); 

shell.setSize(300, 80); 
//shell.pack(); 
shell.open(); 
while (!shell.isDisposed()) { 
if (!display.readAndDispatch()) { 
display.sleep(); 
} 
} 
display.dispose(); 
} 
public static void main(String[] args) { 
new GridLayoutSampleGrabSpace(); 
} 
}

GridLayoutSampleSpan.java

复制代码代码如下:

package swt_jface.demo2; 
import org.eclipse.swt.SWT; 
import org.eclipse.swt.layout.GridData; 
import org.eclipse.swt.layout.GridLayout; 
import org.eclipse.swt.widgets.Button; 
import org.eclipse.swt.widgets.Display; 
import org.eclipse.swt.widgets.List; 
import org.eclipse.swt.widgets.Shell; 
public class GridLayoutSampleSpan { 

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

GridLayout gridLayout = new GridLayout(); 
gridLayout.numColumns = 2; 
gridLayout.makeColumnsEqualWidth = true; 
shell.setLayout(gridLayout); 
Button button1 = new Button(shell, SWT.PUSH); 
button1.setText("button1"); 
button1.setLayoutData(new GridData(GridData.VERTICAL_ALIGN_BEGINNING)); 

List list = new List(shell, SWT.BORDER); 
list.add("item 1"); 
list.add("item 2"); 
list.add("item 3"); 
list.setLayoutData(new GridData(GridData.VERTICAL_ALIGN_CENTER)); 

Button button2 = new Button(shell, SWT.PUSH); 
button2.setText("button #2"); 
GridData gridData = new GridData(GridData.VERTICAL_ALIGN_END); 
gridData.horizontalSpan = 2; 
gridData.horizontalAlignment = GridData.FILL; 
button2.setLayoutData(gridData); 

Button button3 = new Button(shell, SWT.PUSH); 
button3.setText("3"); 
GridData gridData2 = new GridData(GridData.VERTICAL_ALIGN_END); 
gridData2.verticalSpan = 3; 
button3.setLayoutData(gridData2); 

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

下面这个例子布局稍微复杂一点:

复制代码代码如下:

package swt_jface.demo2; 
import org.eclipse.swt.SWT; 
import org.eclipse.swt.custom.CLabel; 
import org.eclipse.swt.graphics.Image; 
import org.eclipse.swt.layout.GridData; 
import org.eclipse.swt.layout.GridLayout; 
import org.eclipse.swt.widgets.Button; 
import org.eclipse.swt.widgets.Combo; 
import org.eclipse.swt.widgets.Display; 
import org.eclipse.swt.widgets.Label; 
import org.eclipse.swt.widgets.Shell; 
import org.eclipse.swt.widgets.Text; 
public class Sample { 

Display display = new Display(); 
Shell shell = new Shell(display); 
public Sample() { 
shell.setText("Book Entry Demo"); 
GridLayout gridLayout = new GridLayout(4, false); 
gridLayout.verticalSpacing = 8; 
shell.setLayout(gridLayout); 
Label label = new Label(shell, SWT.NULL); 
label.setText("Title: "); 
Text title = new Text(shell, SWT.SINGLE | SWT.BORDER); 
GridData gridData = new GridData(GridData.HORIZONTAL_ALIGN_FILL); 
gridData.horizontalSpan = 3; 
title.setLayoutData(gridData); 
label = new Label(shell, SWT.NULL); 
label.setText("Author(s): "); 
Text authors = new Text(shell, SWT.SINGLE | SWT.BORDER); 
gridData = new GridData(GridData.HORIZONTAL_ALIGN_FILL); 
gridData.horizontalSpan = 3; 
authors.setLayoutData(gridData); 
label = new Label(shell, SWT.NULL); 
label.setText("Cover: "); 
gridData = new GridData(); 
gridData.verticalSpan = 3; 
label.setLayoutData(gridData); 
CLabel cover = new CLabel(shell, SWT.NULL); 
gridData = new GridData(GridData.FILL_HORIZONTAL); 
gridData.horizontalSpan = 1; 
gridData.verticalSpan = 3; 
gridData.heightHint = 100; 
gridData.widthHint = 100; 
cover.setLayoutData(gridData); 
label = new Label(shell, SWT.NULL); 
label.setText("Pages"); 
Text pages = new Text(shell, SWT.SINGLE | SWT.BORDER); 
pages.setLayoutData(new GridData(GridData.HORIZONTAL_ALIGN_FILL)); 
label = new Label(shell, SWT.NULL); 
label.setText("Publisher"); 
Text pubisher = new Text(shell, SWT.SINGLE | SWT.BORDER); 
pubisher.setLayoutData(new GridData(GridData.HORIZONTAL_ALIGN_FILL)); 
label = new Label(shell, SWT.NULL); 
label.setText("Rating"); 
Combo rating = new Combo(shell, SWT.READ_ONLY); 
rating.setLayoutData(new GridData(GridData.HORIZONTAL_ALIGN_FILL)); 
rating.add("5"); 
rating.add("4"); 
rating.add("3"); 
rating.add("2"); 
rating.add("1"); 
label = new Label(shell, SWT.NULL); 
label.setText("Abstract:"); 
Text bookAbstract = 
new Text( 
shell, 
SWT.WRAP 
| SWT.MULTI 
| SWT.BORDER 
| SWT.H_SCROLL 
| SWT.V_SCROLL); 
gridData = 
new GridData( 
GridData.HORIZONTAL_ALIGN_FILL | GridData.VERTICAL_ALIGN_FILL); 
gridData.horizontalSpan = 3; 
gridData.grabExcessVerticalSpace = true; 
bookAbstract.setLayoutData(gridData); 
Button enter = new Button(shell, SWT.PUSH); 
enter.setText("Enter"); 
gridData = new GridData(); 
gridData.horizontalSpan = 4; 
gridData.horizontalAlignment = GridData.END; 
enter.setLayoutData(gridData); 
title.setText("Professional Java Interfaces with SWT/JFace"); 
authors.setText("Jack Li Guojie"); 
pages.setText("500pp"); 
pubisher.setText("John Wiley & Sons"); 
cover.setBackground(new Image(display, "C:/eclipse32.gif")); 
bookAbstract.setText( 
"This book provides a comprehensive guide for \n" 
+ "you to create Java user interfaces with SWT/JFace. "); 
shell.pack(); 
shell.open(); 
while (!shell.isDisposed()) { 
if (!display.readAndDispatch()) { 
display.sleep(); 
} 
} 
display.dispose(); 
} 
public static void main(String[] args) { 
new Sample(); 
} 
}

GridLayout提供了很多的属性，可以灵活设置网格的信息。另外，GridLayout 布局提供了GridData类，子组件可以设置相应的GridData，例如“dogPhoto.setLayoutData(gridData)”，GridData可以设置每个组件当做单元格的信息。

14.11.1 GridLayout的风格

GridLayout类提供了GridLayout 布局中划分网格的信息，主要通过以下几个参数进行设置。

NumColumns：通过“gridLayout.numColumns”属性可以设置父组件中分几列显示子组件，如表14-4所示。

表14-4 NumColumns效果

列数	显示效果
numColumns = 1
numColumns = 2
numColumns = 3

MakeColumnsEqualWidth：通过“gridLayout. makeColumnsEqualWidth”属性可以设置父组件中子组件是否有相同的列宽，当MakeColumnsEqualWidth为true时表示每列的列宽相等。

MarginLeft：表示当前组件距离父组件左边距的像素点个数。

MarginRight：表示当前组件距离父组件右边距的像素点个数。

MarginTop：表示当前组件距离父组件上边距的像素点个数。

MarginBottom：表示当前组件距离父组件下边距的像素点个数。

HorizontalSpacing：表示子组件的水平间距。

VerticalSpacing：表示子组件的垂直间距。

SWT(JFace)体验之GridLayout布局

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