Java中的If / Else语句出现问题

Question

I am working on a basic pager system for my dad's dental office. 我正在为我父亲的牙科诊所开发一个基本的寻呼机系统。 Essentially I am recreating this device, but in a much prettier touch screen form using Kindles. 本质上，我正在重新创建此设备，但是使用Kindle以更漂亮的触摸屏形式创建。 Basically, the buttons have 3 state: Off, On, Flashing. 基本上，按钮具有3种状态：关闭，打开，闪烁。 SO the idea is that I want to host a JavaScript back end that all of the Kindles are set on. 因此，我的想法是我想托管所有Kindle都已安装的JavaScript后端。 They can all send and receive updates. 他们都可以发送和接收更新。 I'm having a surprising amount of issues a creating a button that goes through these three states. 创建一个经历这三个状态的按钮时，我遇到了很多问题。

I created a basic counter that displays in a button like this. 我创建了一个基本的计数器，该计数器显示在这样的按钮中。

<body>
<script type="text/javascript">
var state = 0;
function onClick() {
    state += 1;
    document.getElementById("clicks").innerHTML = state;
};
</script>
<button type="button" onClick="onClick()">Click me</button>
<p>State : <a id="clicks">0</a></p>

</body></html>

But I am trying to build a function that will tell the style to loop from the 3rd state back to the first, and I didn't imagine I would have this much trouble. 但是我正在尝试构建一个函数，该函数将告诉样式从第3种状态循环回到第一种状态，而且我没有想到会有那么多麻烦。 So I tested a few variations of if/else conditions, using the assumption that that the state variable was actually holding the value as the displayed numbers were increasing. 所以我测试了if / else条件的一些变化，并假设状态变量实际上随着显示的数字增加而保持该值。 it ended up looking something like this: 最终看起来像这样：

<script>
var state = 0;
function onClick() {
if (state = 0) {
    state += 1;
} else if (state = 1) {
    state += 1;
} else {
state -= 1;
}

but this doesn't function... Clearly I don't get how to use conditional statements... in the first example, is the state variable not actually storing the value? 但这不起作用...显然，我不知道如何使用条件语句...在第一个示例中，状态变量是否未实际存储值？ What am I doing wrong, is it syntax? 我在做什么错，语法吗？

Answer 1

In IF-statements, you check for equality using == or === . 在IF语句中，您使用==或===检查是否相等。 A single = is used purely for assignment. 单个=仅用于分配。

Answer 2

将=更改为== =仅用于分配，而==仅用于同盟

Java中的If / Else语句出现问题

问题描述

2 个解决方案

解决方案1
3 已采纳 2017-06-12 16:49:09

解决方案2
0 2017-06-12 17:01:04

Java中的If / Else语句出现问题

问题描述

2 个解决方案

解决方案1 3 已采纳 2017-06-12 16:49:09

解决方案2 0 2017-06-12 17:01:04

解决方案1
3 已采纳 2017-06-12 16:49:09

解决方案2
0 2017-06-12 17:01:04