集成SDK后运行App报java.lang.NoClassDefFoundError该如何解决

1. 问题


我接入了移动推送SDK，运行时报出java.lang.NoClassDefFoundError找不到某个类，但SDK中明明包含这个类，为什么会这样？

2. 问题原因


如果您的App工程使用了multidex架构，可能会出现java.lang.NoClassDefFoundError，原因在于：推送SDK由于需要在application中进行初始化，所以相关类需要被放到MainDex文件中，否则在app启动时可能会报错。

3. 解决方案


通过修改Gradle构建脚本，可以将一些类显示放到MainDex中：

1. [backcolor=transparent]afterEvaluate [backcolor=transparent]{
2. [backcolor=transparent]    tasks[backcolor=transparent].[backcolor=transparent]matching[backcolor=transparent]{
3. [backcolor=transparent]        it[backcolor=transparent].[backcolor=transparent]name[backcolor=transparent].[backcolor=transparent]startsWith[backcolor=transparent]([backcolor=transparent]'create'[backcolor=transparent])[backcolor=transparent] [backcolor=transparent]&&[backcolor=transparent] it[backcolor=transparent].[backcolor=transparent]name[backcolor=transparent].[backcolor=transparent]endsWith[backcolor=transparent]([backcolor=transparent]'MainDexClassList'[backcolor=transparent])
4. [backcolor=transparent]    [backcolor=transparent]}.[backcolor=transparent]each [backcolor=transparent]{[backcolor=transparent] tk [backcolor=transparent]->
5. [backcolor=transparent]        tk[backcolor=transparent].[backcolor=transparent]doLast [backcolor=transparent]{
6. [backcolor=transparent]            keepMainMultiDex[backcolor=transparent]([backcolor=transparent]tk[backcolor=transparent].[backcolor=transparent]outputFile[backcolor=transparent]);
7. [backcolor=transparent]        [backcolor=transparent]}
8. [backcolor=transparent]    [backcolor=transparent]}
9. [backcolor=transparent]}
11. [backcolor=transparent]/**
12. [backcolor=transparent] * 控制MainDex中的class列表
13. [backcolor=transparent] * 将multidex.keep的内容追加到 maindexlist.txt 中
14. [backcolor=transparent] * @param outputFile
15. [backcolor=transparent] */
16. [backcolor=transparent]def[backcolor=transparent] keepMainMultiDex[backcolor=transparent]([backcolor=transparent]File[backcolor=transparent] outputFile[backcolor=transparent]){
17. [backcolor=transparent]    [backcolor=transparent]File[backcolor=transparent] keepFile [backcolor=transparent]=[backcolor=transparent] file[backcolor=transparent]([backcolor=transparent]"multidex.keep"[backcolor=transparent]);
18. [backcolor=transparent]    outputFile [backcolor=transparent]<<[backcolor=transparent] [backcolor=transparent]'\n'
19. [backcolor=transparent]    outputFile [backcolor=transparent]<<[backcolor=transparent] keepFile[backcolor=transparent].[backcolor=transparent]getText[backcolor=transparent]([backcolor=transparent]'UTF-8'[backcolor=transparent])
20. [backcolor=transparent]}

1. [backcolor=transparent]com[backcolor=transparent]/[backcolor=transparent]alibaba[backcolor=transparent]/[backcolor=transparent]sdk[backcolor=transparent]/[backcolor=transparent]android[backcolor=transparent]/[backcolor=transparent]push[backcolor=transparent]/[backcolor=transparent]securitybox[backcolor=transparent]/[backcolor=transparent]alipush[backcolor=transparent]/[backcolor=transparent]AliPushSecurityBoxService
2. [backcolor=transparent]com[backcolor=transparent]/[backcolor=transparent]alibaba[backcolor=transparent]/[backcolor=transparent]sdk[backcolor=transparent]/[backcolor=transparent]android[backcolor=transparent]/[backcolor=transparent]push[backcolor=transparent]/[backcolor=transparent]CloudPushService
3. [backcolor=transparent]......