- 查阅资料知: AS 升级到4.2.1 Gradle 会默认关闭 task 任务栏
- 手贱误操作关闭Gradle Task 任务栏
File -> Setting -> Experimental -> Gradle ->
Do not build Gradle task list during Gradle sync 取消勾选 ->
apply -> OK -> 回到As 主界面
As 主界面Gradle -> 选中项目右击 -> Reload Gradle Project

File -> Setting -> Experimental -> Gradle ->
Do not build Gradle task list during Gradle sync 取消勾选 ->
apply -> OK -> 回到As 主界面
As 主界面Gradle -> 选中项目右击 -> Reload Gradle Project