SWT(JFace)體驗(yàn)之GridLayout布局

更新時(shí)間：2009年06月25日 11:18:06 作者：

GridLayout 布局的功能非常強(qiáng)大，也是筆者常用的一種布局方式。GridLayout是網(wǎng)格式布局，它把父組件分成一個(gè)表格，默認(rèn)情況下每個(gè)子組件占據(jù)一個(gè)單元格的空間，每個(gè)子組件按添加到父組件的順序排列在表格中。

GridLayout布局

GridLayout 布局的功能非常強(qiáng)大，也是筆者常用的一種布局方式。GridLayout是網(wǎng)格式布局，它把父組件分成一個(gè)表格，默認(rèn)情況下每個(gè)子組件占據(jù)一個(gè)單元格的空間，每個(gè)子組件按添加到父組件的順序排列在表格中。GridLayout提供了很多的屬性，可以靈活設(shè)置網(wǎng)格的信息。另外，GridLayout 布局提供了GridData類，子組件可以設(shè)置相應(yīng)的GridData，例如 “dogPhoto.setLayoutData(gridData)”，GridData可以設(shè)置每個(gè)組件當(dāng)做單元格的信息。

GridLayout的風(fēng)格

GridLayout類提供了GridLayout 布局中劃分網(wǎng)格的信息，主要通過以下幾個(gè)參數(shù)進(jìn)行設(shè)置。

NumColumns：通過“gridLayout.numColumns”屬性可以設(shè)置父組件中分幾列顯示子組件。

MakeColumnsEqualWidth：通過“gridLayout. makeColumnsEqualWidth”屬性可以設(shè)置父組件中子組件是否有相同的列寬，當(dāng)MakeColumnsEqualWidth為true時(shí)表示每列的列寬相等。
MarginLeft：表示當(dāng)前組件距離父組件左邊距的像素點(diǎn)個(gè)數(shù)。
MarginRight：表示當(dāng)前組件距離父組件右邊距的像素點(diǎn)個(gè)數(shù)。
MarginTop：表示當(dāng)前組件距離父組件上邊距的像素點(diǎn)個(gè)數(shù)。
MarginBottom：表示當(dāng)前組件距離父組件下邊距的像素點(diǎn)個(gè)數(shù)。
HorizontalSpacing：表示子組件的水平間距。
VerticalSpacing：表示子組件的垂直間距。

GridData的相關(guān)屬性

GridLayout布局的靈活之處在于它利用網(wǎng)格布局?jǐn)?shù)據(jù)GridData。通過GridData可以設(shè)置子組件在網(wǎng)格中的填充方式、大小邊距等信息，用戶可以通過子組件的setLayoutData方法設(shè)置網(wǎng)格布局?jǐn)?shù)據(jù)。

GridData可以控制子組件在網(wǎng)格中的位置大小等相關(guān)顯示信息。GridData可以設(shè)置如下的一些屬性。

HorizontalAlignment：表示水平對(duì)齊方式。

VerticalAlignment：表示子組件的垂直對(duì)齊方式，值和水平方式一樣。
HorizontalIndent：表示子組件水平偏移多少像素。此屬性和“horizontalAlignment = GridData.BEGINNING”屬性一起使用。

HorizontalSpan：表示組件水平占據(jù)幾個(gè)網(wǎng)格。

GrabExcessHorizontalSpace：表示當(dāng)父組件大小改變時(shí)，子組件是否以水平方向搶占空間。
GrabExcessVerticalSpace：表示當(dāng)父組件大小改變時(shí)，子組件是否以垂直方向搶占空間。
WidthHint：表示子組件的寬度為多少像素（前提是未設(shè)置其他相關(guān)屬性）。
HeightHint：表示子組件的高度為多少像素（前提是未設(shè)置其他相關(guān)屬性）。

另外，GridData可以通過構(gòu)造函數(shù)指定相應(yīng)的屬性值，有興趣的讀者可以參考GridData類的構(gòu)造函數(shù)。

測(cè)試代碼:

GridLayoutSample.java

復(fù)制代碼代碼如下:

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

復(fù)制代碼代碼如下:

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

復(fù)制代碼代碼如下:

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(); 
} 
}

下面這個(gè)例子布局稍微復(fù)雜一點(diǎn):

復(fù)制代碼代碼如下:

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提供了很多的屬性，可以靈活設(shè)置網(wǎng)格的信息。另外，GridLayout 布局提供了GridData類，子組件可以設(shè)置相應(yīng)的GridData，例如“dogPhoto.setLayoutData(gridData)”，GridData可以設(shè)置每個(gè)組件當(dāng)做單元格的信息。

14.11.1 GridLayout的風(fēng)格

GridLayout類提供了GridLayout 布局中劃分網(wǎng)格的信息，主要通過以下幾個(gè)參數(shù)進(jìn)行設(shè)置。

NumColumns：通過“gridLayout.numColumns”屬性可以設(shè)置父組件中分幾列顯示子組件，如表14-4所示。

表14-4 NumColumns效果

列數(shù)	顯示效果
numColumns = 1
numColumns = 2
numColumns = 3

MakeColumnsEqualWidth：通過“gridLayout. makeColumnsEqualWidth”屬性可以設(shè)置父組件中子組件是否有相同的列寬，當(dāng)MakeColumnsEqualWidth為true時(shí)表示每列的列寬相等。

MarginLeft：表示當(dāng)前組件距離父組件左邊距的像素點(diǎn)個(gè)數(shù)。

MarginRight：表示當(dāng)前組件距離父組件右邊距的像素點(diǎn)個(gè)數(shù)。

MarginTop：表示當(dāng)前組件距離父組件上邊距的像素點(diǎn)個(gè)數(shù)。

MarginBottom：表示當(dāng)前組件距離父組件下邊距的像素點(diǎn)個(gè)數(shù)。

HorizontalSpacing：表示子組件的水平間距。

VerticalSpacing：表示子組件的垂直間距。

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