在移动设备应用程序中使用软键盘

• 将焦点放在具有 TextInput 或 TextArea 之类文本输入控件的控件上

• 将控件的 needsSoftKeyboard 属性设置为 true，并将焦点放在该控件上

• 对控件调用 requestSoftKeyboard() 方法（不在 iOS 上）

• 用户将焦点移动到不接收文本输入的控件。当用户手动指向另一个文本输入控件，或者用户按键盘上的返回键，应用程序随之将焦点移到另一个控件时就会发生这种情况。

  如果焦点移动到其他文本输入控件，或移动到 needsSoftKeyboard 属性为 true 的控件，则键盘保持打开状态。

• 用户按下设备上的后退按钮以取消输入。

• 您可通过编程将焦点更改到非交互式控件或将 stage.focus 设置为 null。

<s:TextInput skinClass="spark.skins.mobile.TextInputSkin"/> 
<s:TextArea skinClass="spark.skins.mobile.TextAreaSkin"/>

<?xml version="1.0" encoding="utf-8"?>
<!-- mobile_keyboard/views/UseNextLikeTab.mxml -->
<s:View xmlns:fx="http://ns.adobe.com/mxml/2009" 
        xmlns:s="library://ns.adobe.com/flex/spark" title="Change Focus">
    <fx:Declarations>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
    </fx:Declarations>
    
    <s:layout>
        <s:VerticalLayout paddingTop="10" paddingLeft="10" paddingRight="10"/>
    </s:layout>
    
    <fx:Script>
        <![CDATA[
            private function changeField(ti:TextInput):void {
                // Before changing focus to a new control, set the stage‘s focus to null:
                stage.focus = null;
                
                // Set focus on the TextInput that was passed in:
                ti.setFocus();
            }
        ]]>
    </fx:Script>
    
    <s:HGroup>
        <s:Label text="1:" paddingTop="15"/>
        <s:TextInput id="ti1" prompt="First Name"
                     width="80%"
                     returnKeyLabel="next" 
                     enter="changeField(ti2)"/>     
    </s:HGroup>
    <s:HGroup>
        <s:Label text="2:" paddingTop="15"/>
        <s:TextInput id="ti2" prompt="Middle Initial" 
                     width="80%"
                     returnKeyLabel="next" 
                     enter="changeField(ti3)"/>
    </s:HGroup>
    <s:HGroup>
        <s:Label text="3:" paddingTop="15"/>
        <s:TextInput id="ti3" prompt="Last Name" 
                     width="80%"
                     returnKeyLabel="next" 
                     enter="changeField(ti1)"/>
    </s:HGroup>
    
</s:View>

<?xml version="1.0" encoding="utf-8"?>
<!-- mobile_keyboard/views/CompareMobileKeyPresses.mxml -->
<s:View xmlns:fx="http://ns.adobe.com/mxml/2009" 
        xmlns:s="library://ns.adobe.com/flex/spark" title="Keyboard Events">
    <fx:Declarations>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
    </fx:Declarations>
    
    <s:layout>
        <s:VerticalLayout/>
    </s:layout>
    
    <fx:Script>
        <![CDATA[
            private var storedValueOfText:String = null;
            
            // Compare the new text against the stored value to see what key was pressed.
            private function compareKey(e:Event):void {
                var key:String = "";
                if (storedValueOfText == null) {
                    key = ti1.text.charCodeAt(0).toString(); // Capture the first key pressed.                  
                } else {
                    // Compare the stored value against the current value and extract the difference.
                    for (var i:int = 0; i<ti1.text.length; i++) {
                        if (ti1.text.charAt(i) == storedValueOfText.charAt(i)) {
                            // Do nothing if they‘re equal.
                        } else {                            
                            key = ti1.text.charCodeAt(i).toString();
                        }
                    }
                }
                ti2.text = "The ‘" + key + "‘ key was pressed.";
                storedValueOfText = ti1.text;
            }
        ]]>
    </fx:Script>
    
    <s:TextInput id="ti1" change="compareKey(event)"/>
    <s:TextInput id="ti2" editable="false"/>

</s:View>

<?xml version="1.0" encoding="utf-8"?>
<!-- mobile_text/views/RequestSoftKeyboardExample.mxml -->
<s:View xmlns:fx="http://ns.adobe.com/mxml/2009" 
        xmlns:s="library://ns.adobe.com/flex/spark" title="requestSoftKeyboard()">
    <fx:Declarations>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
    </fx:Declarations>
    
    <s:layout>
        <s:VerticalLayout/> 
    </s:layout>
    
    <fx:Script>
        <![CDATA[
            private function handleButtonClick():void {
                myLabel.requestSoftKeyboard();              
            }
            /* Ok to use keyUp handler on limited screen keyboard. */
            private function handleKeys(event:KeyboardEvent):void {
                var c:int;
                switch(event.keyCode) {
                    case(82): // 82 = "r"                       
                        c = 0xFF0000;
                        break;
                    case(71): // 71 = "g"
                        c = 0x00FF00;
                        break;                      
                    case(66): // 66 = "b"
                        c = 0x0000FF;
                        break;
                }
                event.currentTarget.setStyle("color",c);
            }
        ]]>
    </fx:Script>
    <s:Label id="myLabel" text="This is a label." needsSoftKeyboard="true" keyUp="handleKeys(event)"/>
    <s:Button id="b1" label="Click Me" click="handleButtonClick()"/>
    
</s:View>

<?xml version="1.0" encoding="utf-8"?>
<!-- mobile_keyboard/views/SoftKeyboardEvents.mxml -->
<s:View xmlns:fx="http://ns.adobe.com/mxml/2009" 
        xmlns:s="library://ns.adobe.com/flex/spark" title="Soft Keyboard Events">
    <fx:Declarations>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
    </fx:Declarations>
    
    <s:layout>
        <s:VerticalLayout/> 
    </s:layout>
    
    <s:TextInput prompt="Enter your text"
             softKeyboardActivate="ta1.text+=stage.softKeyboardRect + ‘\n‘"
             softKeyboardDeactivate="ta1.text+=stage.softKeyboardRect + ‘\n‘"
             softKeyboardActivating="ta1.text+=stage.softKeyboardRect + ‘\n‘"/> 

    <s:TextArea id="ta1" width="100%" height="100%" editable="false"/>
    
</s:View>

• 根据剩余可用屏幕空间来调整应用程序大小，以免键盘会与应用程序发生重叠。

• 滚动获得焦点的文本输入控件的父容器，以确保该控件可见。