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ccarray.html
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<!DOCTYPE html>
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<h1 class="sectionedit1" id="ccarray">CCArray</h1>
<div class="level1">
<p>
CCArray 是 quick 中 C++ 层面大量使用的容器。
</p>
<p>
~~
</p>
<p>
对象继承关系：
<a href="ccobject.html" class="wikilink1" title="zh_cn:api:ccobject">CCObject</a> -> CCArray
</p>
<p>
~~
</p>
<p>
在 Lua 里使用 CCArray，最大的问题是如何从 CCArray 中访问对象：
</p>
<pre class="code lua"><span class="kw1">local</span> tag <span class="sy0">=</span> <span class="nu0">100</span>
<span class="co1">-- 取得包含所有子对象的 CCArray</span>
<span class="kw1">local</span> children <span class="sy0">=</span> sprite<span class="sy0">:</span>getChildren<span class="br0">(</span><span class="br0">)</span>
<span class="co1">-- 遍历所有子对象，设置这些子对象的 tag 为特定值</span>
<span class="kw1">for</span> i <span class="sy0">=</span> <span class="nu0">0</span><span class="sy0">,</span> children<span class="sy0">:</span>count<span class="br0">(</span><span class="br0">)</span> <span class="kw1">do</span>
<span class="kw1">local</span> child <span class="sy0">=</span> children<span class="sy0">:</span>objectAtIndex<span class="br0">(</span><span class="nu0">0</span><span class="br0">)</span>
child<span class="sy0">:</span>setTag<span class="br0">(</span>tag<span class="br0">)</span> <span class="co1">-- 这里会出错</span>
<span class="kw1">end</span></pre>
<p>
上述代码之所以出错，是因为 CCArray:objectAtIndex() 返回的对象类型不是对象的实际类型。这样就造成我们无法访问 child 对象的方法。解决这个问题需要用到
<a href="tolua.html" class="wikilink1" title="zh_cn:api:tolua">tolua</a> 模块中的 cast() 方法。
</p>
<pre class="code lua"><span class="co1">-- 遍历所有子对象，设置这些子对象的 tag 为特定值</span>
<span class="kw1">for</span> i <span class="sy0">=</span> <span class="nu0">0</span><span class="sy0">,</span> children<span class="sy0">:</span>count<span class="br0">(</span><span class="br0">)</span> <span class="kw1">do</span>
<span class="kw1">local</span> child <span class="sy0">=</span> tolua<span class="sy0">.</span>cast<span class="br0">(</span>children<span class="sy0">:</span>objectAtIndex<span class="br0">(</span><span class="nu0">0</span><span class="br0">)</span><span class="sy0">,</span> <span class="st0">"CCNode"</span><span class="br0">)</span>
child<span class="sy0">:</span>setTag<span class="br0">(</span>tag<span class="br0">)</span> <span class="co1">-- 这里会出错</span>
<span class="kw1">end</span></pre>
<p>
cast() 方法强制转换对象类型，以便让我们访问对象方法。但这个方法相当危险，如果我们进行了错误的类型转换，那么接下来调用对象方法就有可能导致整个游戏崩溃。
</p>
<p>
所以在 Lua 里，使用 CCArray 一定要非常小心。
</p>
<p>
~
</p>
<p>
常用方法：
</p>
<pre class="code lua"><span class="kw1">local</span> array <span class="sy0">=</span> CCArray<span class="sy0">:</span>create<span class="br0">(</span><span class="br0">)</span> <span class="co1">-- 创建一个 CCArray 对象</span>
array<span class="sy0">:</span>addObject<span class="br0">(</span>display<span class="sy0">.</span>newNode<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span> <span class="co1">-- 添加一个对象到 CCArray 中</span>
array<span class="sy0">:</span>insertObject<span class="br0">(</span>display<span class="sy0">.</span>newNode<span class="br0">(</span><span class="br0">)</span><span class="sy0">,</span> <span class="nu0">0</span><span class="br0">)</span> <span class="co1">-- 在指定位置（0 开始的索引）插入一个对象</span>
<span class="kw3">print</span><span class="br0">(</span>array<span class="sy0">:</span>count<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span> <span class="co1">-- 输出数组中的对象总数</span>
<span class="co1">-- 取得指定对象，并用 tolua.cast() 强制转换类型</span>
<span class="kw1">local</span> node <span class="sy0">=</span> tolua<span class="sy0">.</span>cast<span class="br0">(</span>array<span class="sy0">:</span>objectAtIndex<span class="br0">(</span><span class="nu0">0</span><span class="br0">)</span><span class="sy0">,</span> <span class="st0">"CCNode"</span><span class="br0">)</span>
<span class="co1">-- 删除最后一个对象</span>
array<span class="sy0">:</span>removeLastObject<span class="br0">(</span><span class="br0">)</span>
<span class="co1">-- 删除指定位置的对象</span>
array<span class="sy0">:</span>removeObjectAtIndex<span class="br0">(</span><span class="nu0">0</span><span class="br0">)</span>
<span class="co1">-- 删除所有对象</span>
array<span class="sy0">:</span>removeAllObjects<span class="br0">(</span><span class="br0">)</span></pre>
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<div class="docInfo">zh_cn/api/ccarray.txt · Last modified: 2013/08/19 16:19 by Yu Lei Liao</div>
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