今天用android studio 编译项目时，出现aapt.exe finished with non-zero exit value 3错误，重启as，rebuild ， clean ，升级都不行。

这种问题一般都是资源文件或者.9图格式不对。能把日志打印出来就好。怎么做？在android studio的终端中输入命令

gradlew processDebugResources --debug

等一会儿：

1:52:04.381 [DEBUG] [org.gradle.process.internal.DefaultExecHandle] Changing state to: FAILED

11:52:04.381 [DEBUG] [org.gradle.process.internal.DefaultExecHandle] Process 'command 'D:\Android\sdk\build-tools\27.0.3\aapt.exe'' finished with exit value 1 (state: FAILED)

11:52:04.402 [ERROR] [org.gradle.api.Project] E:\AndroidWorkSpace\VehicleNumPhone\app\src\main\res\layout\drop_down_menu.xml:82:35-41: AAPT: String types not allowed (at 'textSize' with value '16dpdp').

11:52:04.402 [ERROR] [org.gradle.api.Project] E:\AndroidWorkSpace\VehicleNumPhone\app\build\intermediates\res\merged\debug\layout\drop_down_menu.xml:75: error: Error: String types not allowed (at 'textSize' with value '16dpdp').

单位写错了！！！！

标记一下。