当我放入onPress地图循环时,它不起作用.怎么解决?
var PageOne = React.createClass({
_handlePress() {
this.props.navigator.push({id: 2,});
},
render () {
return (
<View>
<TouchableOpacity onPress={this._handlePress}> //work here
<Text> One </Text>
</TouchableOpacity>
<View style={styles.albums}>
{
list.map(function(item, index){
return (
<TouchableOpacity key={index} onPress={this._handlePress}> //doesn't work hehre
<Text>{item}</Text>
</TouchableOpacity>
)
})
}
</View>
</View>
);
}
});
Run Code Online (Sandbox Code Playgroud) 在我的新项目中,当我点击一个按钮时,它会从底部弹出一个菜单视图.
和代码:
blackView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleDismiss)))
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和handleDismiss功能:
@objc func handleDismiss(callback:(() -> ())?) {
UIView.animate(withDuration: 0.3, animations: {
self.blackView.alpha = 0
//......
}
}) { (completed: Bool) in
callback?()
}
}
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然后我点击菜单视图的Cancel单元格,handleDismiss用callback参数调用该函数.它正在工作.
if item.icon == "close" {
handleDismiss(callback: {
print("callback now")
})
}
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但如果我点击黑色蒙版视图(触发器 action: #selector(handleDismiss))),它的错误如下:
有没有人有想法?
我开始玩榆树语.我正在制作一个基本的网页,我想让我的导航栏在滚动时粘到顶部.
我希望能够让我的模型对从页面顶部向下滚动的距离作出反应.
我有两个问题:
$(window).scrollTop()但没有JQuery我有以下HTML代码:
<ul>
<li>Text</li> <!-- number:0; means first one-->
<li>Text</li> <!-- number:1; second one-->
<li>Text</li> <!-- number:2; third one-->
<li>Text</li> <!-- number:3 -->
<li>Text</li> <!-- number:4 -->
<li>Text</li> <!-- number:5 -->
</ul>
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在我的方法中,number为每个设置一个属性li
i = 0;
$('li').each(function()
{
$(this).attr('number',i);
i++;
});
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用$(this).attr('number')得到它的数量;
这里是jsFiddle DEMO http://jsfiddle.net/8tpab84s/,正在工作
但我认为方法很复杂,如果DOM li要改变,我需要再次设置数字属性.
是否有更简单的方法来代替这种方法?没有设置任何属性.
感谢您的答复.
下面的代码片段是我的滑块jQuery,但它停在最后一张图片上,而不是再循环到第一张图片.有任何想法吗?
function cycleImages() {
var $active = $('#cycler .active');
var $next = ($active.next().length>0) ? $active.next():$('cycler img:first');
$next.css('z-index', 2);
$active.fadeOut(1500, function () {
$active.css('z-index', 1).show().removeClass('active');
$next.css('z-index', 5).addClass('active');
});
}
$(document).ready(function () {
setInterval('cycleImages()', 4000);
})
Run Code Online (Sandbox Code Playgroud) 我一直试图复制Duncan Donut示例HEAD FIRST JAVASCRIPT,但该函数subTotal()永远不会被onchange事件触发,当我查看HTML REFERENCE时,我没有在列表中找到任何onchange事件.
Duncan.html
<html>
<head><title>Duncan Online Donut's Service</title></head>
<script type="text/javascript">
function subTotal(){
document.write("working");
const TAXRATE = 0.095;
const DONUTRATE = 0.5;
var tax = 0;
var subTotal = 0;
var total = 0;
var cakedonut = parseInt(document.getElementById("cakedonut").value);
var glazedonut = parseInt(document.getElementById("glazedonut").value);
if(isNaN(cakedonut))
cakedonut = 0;
if(isNaN(glazedonut))
glazedounut = 0;
subTotal = (cakedonut + glazedonut)* DONUTRATE ;
tax = subTotal * TAXRATE ;
total = subTotal + tax ;
document.getElementById("subTotal").value = "$" …Run Code Online (Sandbox Code Playgroud) HTML:
<div>
<span><a href="profile.html"><img class="propic" src="propic.jpg"/></a></span>
<span> <h1 id="header"><a href="index.html">B. L. ROSENBERG</a></h1> </span>
</div>
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CSS:
#header{
/*problem line:*/
color:white;
margin-top:-85px;
margin-left: auto;
margin-right:auto;
z-index:-1;
width:95%;
background-color:#303030;
font-size: 36px;
letter-spacing: 33px;
font-family: Futura,"Trebuchet MS",Arial,sans-serif;
text-align: center;
}
.propic {
z-index:1;
top:20px;
width: 120px;
height: 120px;
border-radius: 50%;
}
.propic:hover{
border-style: solid;
border-width:1px;
border-color:#CC0000;}
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