注意：以下文档只适用于TOP接口，请谨慎使用！
注意：以下文档只适用于TOP接口，请谨慎使用！
应用提供了全局的 getApp() 方法，可获取当前应用实例，一般用于在子页面中获取顶层应用。
1 2 | <span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">var app = getApp();</span></span><span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">console.log(app.globalData); // 获取 globalData</span></span> |
使用过程中，请注意以下几点：
1）App() 函数中不可以调用 getApp()，可使用 this 可以获取当前应用实例。
2）通过 getApp() 获取实例后，请勿私自调用生命周期回调函数。
3）请区分全局变量及页面局部变量，比如：
1 2 3 4 5 6 7 | <span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">// a.js</span></span><span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">// localValue 只在 a.js 有效</span></span><span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">var localValue = 'a';</span></span><span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">// 获取 app 实例</span></span><span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">var app = getApp();</span></span><span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">// 拿到全局数据，并改变它</span></span><span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">app.globalData++;</span></span> |
1 2 3 4 5 | <span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">// b.js</span></span><span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">// localValue 只在 b.js 有效</span></span><span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">var localValue = 'b';</span></span><span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">// 如果 a.js 先运行，globalData 会返回 2</span></span><span class="lake-preview-line" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"><span class="lake-preview-line-number lake-lm-pad-level-0" style="color: rgb(191, 191, 191); margin: 0px 8px 0px 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);"></span><span class="lake-preview-codeblock-content" style="color: rgb(89, 89, 89); margin: 0px; padding: 0px; background: none 0% 0% / auto repeat scroll padding-box border-box rgba(0, 0, 0, 0);">console.log(getApp().globalData);</span></span> |
a.js 和 b.js 两个文件中都声明了变量 localValue，但并不会互相影响，因为各个文件声明的局部变量和函数只在当前文件下有效。
