FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':app:compileDebugJavaWithJavac'.
> Could not find tools.jar. Please check that D:\ProgramFile\java\jre8 contains a valid JDK installation.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
BUILD FAILED
Total time: 2.558 secs
Could not install the app on the device, read the error above for details.
Make sure you have an Android emulator running or a device connected and have
set up your Android development environment:
https://facebook.github.io/react-native/docs/getting-started.html
错误原因：
jdk环境配置问题
解决方案：
在环境变量中添加名JAVA_HOME的变量,值为JDK路径
"我的电脑"右键“属性”->高级系统设置->环境变量 -> 新建JAVA_HOME,然后在Path添加
%JAVA_HOME%\bin