通常情况下，仅在点击 TextField 对象时才会打开虚拟键盘。可以配置 InteractiveObject 类的一个实例，以便在其获得焦点时打开虚拟键盘。
若要配置 InteractiveObject 实例以打开软键盘，请将其
needsSoftKeyboard
属性设置为
true
。每当对象分配到 stage focus 属性时，将自动打开软键盘。此外，还可以通过调用 InteractiveObject 的
requestSoftKeyboard()
方法来开启键盘。
下面的示例演示了如何对 InteractiveObject 编程，使之作为文本输入字段。示例中的 TextInput 类设置
needsSoftKeyboard
属性，以便在需要时开启键盘。然后，该对象侦听
keyDown
事件并将键入的字符插入字段。
该示例使用 Flash 文本引擎附加和显示键入的任何文本，并处理一些重要事件。为简单起见，该示例未实现完整功能的文本字段。
package {
import flash.geom.Rectangle;
import flash.display.Sprite;
import flash.text.engine.TextElement;
import flash.text.engine.TextBlock;
import flash.events.MouseEvent;
import flash.events.FocusEvent;
import flash.events.KeyboardEvent;
import flash.text.engine.TextLine;
import flash.text.engine.ElementFormat;
import flash.events.Event;
public class TextInput extends Sprite
{
public var text:String = " ";
public var textSize:Number = 24;
public var textColor:uint = 0x000000;
private var _bounds:Rectangle = new Rectangle( 0, 0, 100, textSize );
private var textElement: TextElement;
private var textBlock:TextBlock = new TextBlock();
public function TextInput( text:String = "" )
{
this.text = text;
this.scrollRect = _bounds;
this.focusRect= false;
//Enable keyboard support
this.needsSoftKeyboard = true;
this.addEventListener(MouseEvent.MOUSE_DOWN, onSelect);
this.addEventListener(FocusEvent.FOCUS_IN, onFocusIn);
this.addEventListener(FocusEvent.FOCUS_OUT, onFocusOut);
//Setup text engine
textElement = new TextElement( text, new ElementFormat( null, textSize, textColor ) );
textBlock.content = textElement;
var firstLine:TextLine = textBlock.createTextLine( null, _bounds.width - 8 );
firstLine.x = 4;
firstLine.y = 4 + firstLine.totalHeight;
this.addChild( firstLine );
}
private function onSelect( event:MouseEvent ):void
{
stage.focus = this;
}
private function onFocusIn( event:FocusEvent ):void
{
this.addEventListener( KeyboardEvent.KEY_DOWN, onKey );
}
private function onFocusOut( event:FocusEvent ):void
{
this.removeEventListener( KeyboardEvent.KEY_UP, onKey );
}
private function onKey( event:KeyboardEvent ):void
{
textElement.replaceText( textElement.text.length, textElement.text.length, String.fromCharCode( event.charCode ) );
updateText();
}
public function set bounds( newBounds:Rectangle ):void
{
_bounds = newBounds.clone();
drawBackground();
updateText();
this.scrollRect = _bounds;
//force update to focus rect, if needed
if( this.stage!= null && this.focusRect && this.stage.focus == this )
this.stage.focus = this;
}
private function updateText():void
{
//clear text lines
while( this.numChildren > 0 ) this.removeChildAt( 0 );
//and recreate them
var textLine:TextLine = textBlock.createTextLine( null, _bounds.width - 8);
while ( textLine)
{
textLine.x = 4;
if( textLine.previousLine != null )
{
textLine.y = textLine.previousLine.y +
textLine.previousLine.totalHeight + 2;
}
else
{
textLine.y = 4 + textLine.totalHeight;
}
this.addChild(textLine);
textLine = textBlock.createTextLine(textLine, _bounds.width - 8 );
}
}
private function drawBackground():void
{
//draw background and border for the field
this.graphics.clear();
this.graphics.beginFill( 0xededed );
this.graphics.lineStyle( 1, 0x000000 );
this.graphics.drawRect( _bounds.x + 2, _bounds.y + 2, _bounds.width - 4, _bounds.height - 4);
this.graphics.endFill();
}
}
}
下面的主应用程序类演示了当键盘开启或设备方向更改时如何使用 TextInput 类和管理应用程序布局。主类创建一个 TextInput 对象并设置其边界以填充舞台。当软键盘开启或舞台大小更改时，该类调整 TextInput 对象的大小。该类侦听 TextInput 对象的 soft keyboard 事件以及舞台的 resize 事件。无论事件的原因如何，应用程序都会确定舞台的可见区域，并调整输入控件的大小以填充该区域。当然，在实际应用程序中，需要更复杂的布局算法。
package {
import flash.display.MovieClip;
import flash.events.SoftKeyboardEvent;
import flash.geom.Rectangle;
import flash.events.Event;
import flash.display.StageScaleMode;
import flash.display.StageAlign;
public class CustomTextField extends MovieClip {
private var customField:TextInput = new TextInput("Input text: ");
public function CustomTextField() {
this.stage.scaleMode = StageScaleMode.NO_SCALE;
this.stage.align = StageAlign.TOP_LEFT;
this.addChild( customField );
customField.bounds = new Rectangle( 0, 0, this.stage.stageWidth, this.stage.stageHeight );
//track soft keyboard and stage resize events
customField.addEventListener(SoftKeyboardEvent.SOFT_KEYBOARD_ACTIVATE, onDisplayAreaChange );
customField.addEventListener(SoftKeyboardEvent.SOFT_KEYBOARD_DEACTIVATE, onDisplayAreaChange );
this.stage.addEventListener( Event.RESIZE, onDisplayAreaChange );
}
private function onDisplayAreaChange( event:Event ):void
{
//Fill the stage if possible, but avoid the area covered by a keyboard
var desiredBounds = new Rectangle( 0, 0, this.stage.stageWidth, this.stage.stageHeight );
if( this.stage.stageHeight - this.stage.softKeyboardRect.height < desiredBounds.height )
desiredBounds.height = this.stage.stageHeight - this.stage.softKeyboardRect.height;
customField.bounds = desiredBounds;
}
}
}
注：
当
scaleMode
属性设置为
noScale
时，舞台仅调度 resize 事件以响应方向更改。在其他模式中，舞台尺寸不发生更改；而是通过缩放内容来补偿方向更改。
