SWT當(dāng)中的GridLayout是一個(gè)非常靈活的控件,但是在使用起來(lái)需要在控制上下一番功夫.

大家都知道,JAVA在寫(xiě)編寫(xiě)窗口程序的時(shí)候,物件的添加,放置 操作起來(lái)要比.net費(fèi)勁的多,但是如果用好了相關(guān)org.eclipse.layout.*包當(dāng)中的相關(guān)類,也會(huì)寫(xiě)出十分漂亮的界面程序.

下面大家先看一個(gè)程序:

源碼如下:

package com.layout;

import org.eclipse.swt.widgets.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.SWT;

public class CopyOfGridLayoutExc {
?
?public static void main(String[] args) {

??Display display = new Display();

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

???? shell.setText("Find (GridLayout)");

???? Label label = new Label(shell, SWT.NONE);

???? label.setText("Find what:");

???? Text text = new Text(shell, SWT.BORDER);

???? Button findButton = new Button(shell, SWT.PUSH);

???? findButton.setText("Find Next");

???? Group group = new Group(shell, SWT.NONE);

???? group.setLayout(new RowLayout());

???? Button upButton = new Button(group, SWT.RADIO);

???? upButton.setText("Up");

???? Button downButton = new Button(group, SWT.RADIO);

???? downButton.setText("Down");

???? downButton.setSelection(true);

???? group.setText("Direction");

???? Button cancelButton = new Button(shell, SWT.PUSH);

???? cancelButton.setText("Cancel");

?

???? /* Use a GridLayout to position the controls */

???? Monitor monitor = shell.getMonitor();

???? int width = monitor.getClientArea().width / 10;

???? GridLayout layout = new GridLayout(4, false);

???? layout.marginWidth = layout.marginHeight = 14;//layout leave's the window's space

???? shell.setLayout(layout);

???? GridData labelData =

???????? new GridData(SWT.FILL, SWT.CENTER, false, false);

???? label.setLayoutData(labelData);

???? GridData textData =

???????? new GridData(SWT.FILL,SWT.CENTER,true,false,2,1);

???? textData.widthHint = width;

???? text.setLayoutData(textData);

???? GridData findData =

???????? new GridData(SWT.FILL, SWT.CENTER, false, false);

???? findButton.setLayoutData(findData);

???? GridData groupData =

???????? new GridData(SWT.RIGHT,SWT.TOP,false,false,3,1);

???? group.setLayoutData(groupData);

???? GridData cancelData =

???????? new GridData(SWT.FILL, SWT.TOP, false, false);

???? cancelButton.setLayoutData(cancelData);

?

???? shell.pack();

???? shell.open();

???? while (!shell.isDisposed()) {

???????? if (!display.readAndDispatch()) display.sleep();

???? }

???? display.dispose();

?}

}



這其中我們?cè)谑褂玫臅r(shí)候應(yīng)該要注意以下幾點(diǎn):

1.要選擇自己適合 的Layout類型.GridLayout適合于多種情況,它大部分情況是使用在較為復(fù)雜的界面編程當(dāng)中,因?yàn)閺?fù)雜的界面會(huì)有相當(dāng)多的控件.



2.GridData的使用將是一個(gè)控制界面顯示的主要類.通過(guò)使用GridData我們可以很好的控制界面.

?? 其中GridData的構(gòu)造函數(shù)比較多,但是相關(guān)的使用我們都應(yīng)該熟悉,特別是上面源程序當(dāng)中使用的那個(gè)構(gòu)造函數(shù),在使用起來(lái)更容易控制GridLayout的布局.通過(guò)horizantalSpan,VerticalSpan來(lái)控制控件所占用的單元格,這樣就會(huì)控制其它控制是否在一列當(dāng)中顯示還是在幾列當(dāng)中顯示.前提是通過(guò)GridLayout.numColumns來(lái)設(shè)置列數(shù).

3.如果不設(shè)置GridData那么相關(guān)的控件都會(huì)按照相關(guān)的建立順序加入到GridLayout當(dāng)中.GridData不能控制控件的顯示順序,而相關(guān)順序是對(duì)象的建立順序來(lái)控制的.這一點(diǎn)不要與GridData混淆了.

希望寫(xiě)這篇文章對(duì)大家學(xué)習(xí)SWT有用.