How to fix INSTALL_FAILED_TEST_ONLY error

Reference:

https://www.jianshu.com/p/8f5730cab8fc
http://www.cnblogs.com/yongfengnice/p/7814016.html
https://blog.csdn.net/chf1142152101/article/details/70738868

Solution:

1. Add the following line into gradle.properties

    ......
    android.injected.testOnly=false


2. Click Android Studio "Build -> BuildAPK(s)" to generate apk

3. Sign key
4. If gradle version is test version, revise it to release version

buildscript { repositories { jcenter() } dependencies { classpath 'com.android.tools.build:gradle:2.4.0-alpha3' //版本为测试版 } }