GWT GWT. Label. Java GWT. com.google.gwt.user.client.ui package

Transcription

1 GWT GWT GWT Java HTML GWT (Widget) Java com.google.gwt.user.client.ui package 1 2 GWT Label Constructors: public Label() public Label(String text) public Label(String text, boolean wordwrap) wordwrap true public String gettext() public void settext(string text) 3 4

2 HTML Label HTML tag (ex:, ) HTML <div> tag A widget that can contain arbitrary HTML. This widget uses a <div> element, causing it to be displayed with block layout. If you only need a simple label (text, but not HTML), then the Label widget is more appropriate, as it disallows the use of HTML, which can lead to potential security issues if not used properly. Constructors: public HTML(): Creates an empty HTML widget. public HTML(String html): Creates an HTML widget with the specified HTML contents. public HTML(String html, boolean wordwrap): Creates an HTML widget with the specified contents, optionally treating it as HTML, and optionally disabling word wrapping. 5 HTML Methods: public String gethtml() : Gets this object's contents as HTML. public void sethtml(string html): Sets the label's content to the given HTML. See Label.setText(String) for details on potential effects on direction and alignment Hyperlink HTML A widget that serves as an "internal" hyperlink. That is, it is a link to another state of the running application. When clicked, it will create a new history frame using History.newItem(java.lang.String), but without reloading the page. GWT History If you want an HTML hyperlink (<a> tag) without interacting with the history system, use Anchor instead. Being a true hyperlink, it is also possible for the user to "right-click, open link in new window", which will cause the application to be loaded in a new window at the state specified by the hyperlink. Hyperlink Constructors: public Hyperlink(): Creates an empty hyperlink. public Hyperlink(String text, String targethistorytoken): Creates a hyperlink with its text and target history token specified. public Hyperlink(String text, boolean ashtml, String targethistorytoken): Creates a hyperlink with its text and target history token specified. ashtml: true to treat the specified text as html Methods: public String gettext(): Gets this object's text. public String gethtml(): Gets this object's contents as HTML.

3 GWT (Form) (form) (Textbox) (RadioButton) (CheckBox) (ListBox) (Button) FormPanel FormPanel HTML <Form> tag server : FormPanel form=new FormPanel(); : public void setmethod(string method): Sets the HTTP method used for submitting this form. This should be either METHOD_GET or METHOD_POST. Ex:form.setMethod(FormPanel.METHOD_POST); Ex:form.setMethod(FormPanel.METHOD_GET); FormPanel : public void setaction(string url): Sets the 'action' associated with this form. This is the URL to which it will be submitted. Ex: form.setaction( /somewhere ); : TextBox userid=new TextBox(); form.add(userid); TextBox TextBox tb=new TextBox(); String str=tb.gettext(); 10 tb.setmaxlength(10); tb.setvisiblelength(6); TextBox tb.setwidth( 120px );

4 TextArea :gwt-textarea String str=ta.gettext(); TextArea ta.setcharacterwidth(30); ta.setvisiblelines(8); ListBox :gwt-listbox ListBox list=new ListBox(); ListBox : list.add( xxx ); public void setvisibleitemcount(int visibleitems) RadioButton :gwt-radiobutton : public RadioButton(String GroupName, String RbLabel) RadioButton rb0=new RadioButton( color, blue ); RadioButton rb1=new RadioButton( color, red ); RadioButton rb2=new RadioButton( color, green ); FlowPanel panel=new FlowPanel(); panel.add(blue); panel.add(red); panel.add(green); CheckBox :gwt-checkbox : CheckBox cb=new CheckBox( xxx ); cb.setvalue(true); cb.setname( agree ); cb.setenabled(true); : cb.settext( xxx );

5 Button :gwt-button : Button send=new Button( ); send.click(); GWT Designer p.5-9 (event) (Listener): GWT Listener listener (Event Handler) Java com.google.gwt.event.dom.client

6 - : public HandlerRegistration addclickhandler(clickhandle r handler) Interface ClickHandler method: void onclick(clickevent event) Label msg=new Label(); TextBox host=new TextBox(); Button connect=new Button( ); connect.addclickhandler(new ClickHandler(){ public void onclick(clickevent event){ String ip=host.gettext(); msg.settext( +ip+. ); } }); - Interface EntryPoint: It contains the code that executes when you launch the application. Typically, the types of things you do in the onmoduleload() method are: create new user interface components set up handlers for events modify the browser DOM in some way void onmoduleload(): called automatically by loading a module that declares an implementing class as an entry point. - public class Category implements EntryPoint, ClickHandler{ Label msg; public void onmoduleload() { RootPanel rootpanel=rootpanel.get(); Button b1=new Button( 3C ); rootpanel.add(b1, 31,20); b1.addclickhandler(this); /* Category Click */ msg=new Label( ); rootpanel.add(msg, 41,52); public void onclick(clickevent event){ Button b =(Button) event.getsource(); msg.settext(b.gettext()); } 23 } Show events 24

7

8 city/area ItemVisibleCount 1. city, change onchange code : package com.gb2.client; import com.google.gwt.core.client.entrypoint; import com.google.gwt.user.client.ui.rootpanel; import com.google.gwt.user.client.ui.verticalpanel; import com.google.gwt.user.client.ui.label; import com.google.gwt.user.client.ui.listbox; import com.google.gwt.event.dom.client.changehandler; import com.google.gwt.event.dom.client.changeevent; public class AddPost implements EntryPoint { private ListBox area; private ListBox city; public void onmoduleload() { // TODO Auto-generated method stub RootPanel rootpanel=rootpanel.get(); Label lblnewlabel = new Label("\u7E23\u5E02:"); rootpanel.add(lblnewlabel, 0, 10); lblnewlabel.setsize("42px", "20px"); Label label = new Label("\u5340\u57DF:"); rootpanel.add(label, 156, 10); city = new ListBox(); city.additem("\u53f0\u5317\u5e02","1"); city.additem("\u57fa\u9686\u5e02","2"); area = new ListBox(); 32

9 rootpanel.add(area, 208, 10); area.setsize("84px", "24px"); area.setvisibleitemcount(1); rootpanel.add(city, 48, 10); city.setvisibleitemcount(1); area.additem("\u842c\u83ef\u5340"); area.additem("\u58eb\u6797\u5340"); area.additem("\u4fe1\u7fa9\u5340"); city.addchangehandler(new ChangeHandler() { public void onchange(changeevent event) { area.clear(); String selectvalue=city.getvalue(city.getselectedindex()); int n=integer.parseint(selectvalue); switch(n){ case 1: area.additem("\u842c\u83ef\u5340"); area.additem("\u58eb\u6797\u5340"); area.additem("\u4fe1\u7fa9\u5340"); break; case 2: area.additem("\u4ec1\u611b\u5340"); area.additem("\u4fe1\u7fa9\u5340"); area.additem("\u4e2d\u6b63\u5340"); break; } } }); }/* end of onmoduleload */ } HTML!! Run : 35 36

10 : ListBox ListBox::public void additem(java.lang.string item, java.lang.string value): Adds an item to the list box, specifying an initial value for the item. item: ListBox value: index ( ) / value item item! index value GWT FlowPanel: HorizontalPanel: FlowPanel VerticalPanel DockLayoutPanel: Grid: HTML 37 GWT Grid grid=new Grid(2,3); grid.setborderwidth(1); for(int row=0;row<2;row++) for (int col=0;col<3;col++) grid.settext(row,col,row+, +col); GWT FlexTable: HTML Grid cell FlexTable flextable=new FlexTable(); rootpanel.add(flextable,238,23); flextable.setsize( 155px, 100px ); flextable.setborderwidth(1); flextable.setwidget(0,0,new Label( ABC )); flextable.setwidget(0,1,new Label( DEF )); flextable.setwidget(0,2,new Label( GHI )); flextable.setwidget(1,0,new Label( 123 )); flextable.setwidget(1,1,new Label( 456 )); flextable.setwidget(1,2,new Label( 789 )); 39 40