修改app下build.gradle文件
android {compileSdkVersion 29defaultConfig {applicationId \"com.example.z.test1\"minSdkVersion 29targetSdkVersion 29versionCode 1versionName \"1.0\"testInstrumentationRunner \"android.support.test.runner.AndroidJUnitRunner\"}降低版本我这边写成15
android {compileSdkVersion 29defaultConfig {applicationId \"com.example.z.test1\"minSdkVersion 15targetSdkVersion 29versionCode 1versionName \"1.0\"testInstrumentationRunner \"android.support.test.runner.AndroidJUnitRunner\"}