动作脚本3：鼠标悬停时Alpha更改

| 尝试使它停留在图像上时出现我的文本：

gticar.addEventListener( MouseEvent.ROLL_OVER, roll );
function roll ( evt:MouseEvent ) {
    gtiText.alpha = 1;
}

我究竟做错了什么？该符号的Alpha当前为0。完整代码视图：

import flash.events.MouseEvent;

// Stop the showcase on the homepage (frame 2)

stop();

// Preload sound clip for buttons

var snd:Sound = new Sound();
snd.load(new URLRequest(\"city-traffic-edit.mp3\"));

// Buttons

homeButton.addEventListener( MouseEvent.CLICK, home );
function home( evt:MouseEvent ) {
    gotoAndStop(2);
    snd.play();
}

galleryButton.addEventListener( MouseEvent.CLICK, gallery );
function gallery( evt:MouseEvent ) {
    gotoAndStop(3);
    snd.play();
}

mk1Button.addEventListener( MouseEvent.CLICK, mk1 );
function mk1( evt:MouseEvent ) {
    gotoAndStop(4);
    snd.play();
}

mk2Button.addEventListener( MouseEvent.CLICK, mk2 );
function mk2( evt:MouseEvent ) {
    gotoAndStop(5);
    snd.play();
}

mk3Button.addEventListener( MouseEvent.CLICK, mk3 );
function mk3( evt:MouseEvent ) {
    gotoAndStop(6);
    snd.play();
}

mk4Button.addEventListener( MouseEvent.CLICK, mk4 );
function mk4( evt:MouseEvent ) {
    gotoAndStop(7);
    snd.play();
}

mk5Button.addEventListener( MouseEvent.CLICK, mk5 );
function mk5( evt:MouseEvent ) {
    gotoAndStop(8);
    snd.play();
}

mk6Button.addEventListener( MouseEvent.CLICK, mk6 );
function mk6( evt:MouseEvent ) {
    gotoAndStop(9);
    snd.play();
}

gticar.addEventListener( MouseEvent.ROLL_OVER, roll );
function roll ( evt:MouseEvent ) {
    gtiText:alpha = 1.0;
}