Android studio 编译时出现：Caused by: com.android.builder.errors.EvalIssueException: This project uses AndroidX dependencies, but the ‘android.useAndroidX’ property is not enabled. Set this property to true in the gradle.properties file and retry.
java.lang.RuntimeException: java.lang.RuntimeException: Duplicate class android.support.v4.app.INotificationSideChannel found in modules core-1.3.1-runtime.jar (androidx.core:core:1.3.1) and support-compat-26.0.0-runtime.jar (com.android.support:support-compat:26.0.0)
Duplicate class android.support.v4.app.INotificationSideChannel$Stub found in modules core-1.3.1-runtime.jar (androidx.core:core:1.3.1) and support-compat-26.0.0-runtime.jar (com.android.support:support-compat:26.0.0)
Duplicate class android.support.v4.app.INotificationSideChannel$Stub$Proxy found in modules core-1.3.1-runtime.jar (androidx.core:core:1.3.1) and support-compat-26.0.0-runtime.jar (com.android.support:support-compat:26.0.0)
Duplicate class android.support.v4.os.IResultReceiver found in modules core-1.3.1-runtime.jar (androidx.core:core:1.3.1) and support-compat-26.0.0-runtime.jar (com.android.support:support-compat:26.0.0)
Duplicate class android.support.v4.os.IResultReceiver$Stub found in modules core-1.3.1-runtime.jar (androidx.core:core:1.3.1) and support-compat-26.0.0-runtime.jar (com.android.support:support-compat:26.0.0)
Duplicate class android.support.v4.os.IResultReceiver$Stub$Proxy found in modules core-1.3.1-runtime.jar (androidx.core:core:1.3.1) and support-compat-26.0.0-runtime.jar (com.android.support:support-compat:26.0.0)
Duplicate class android.support.v4.os.ResultReceiver found in modules core-1.3.1-runtime.jar (androidx.core:core:1.3.1) and support-compat-26.0.0-runtime.jar (com.android.support:support-compat:26.0.0)
Duplicate class android.support.v4.os.ResultReceiver$1 found in modules core-1.3.1-runtime.jar (androidx.core:core:1.3.1) and support-compat-26.0.0-runtime.jar (com.android.support:support-compat:26.0.0)
Duplicate class android.support.v4.os.ResultReceiver$MyResultReceiver found in modules core-1.3.1-runtime.jar (androidx.core:core:1.3.1) and support-compat-26.0.0-runtime.jar (com.android.support:support-compat:26.0.0)
Duplicate class android.support.v4.os.ResultReceiver$MyRunnable found in modules core-1.3.1-runtime.jar (androidx.core:core:1.3.1) and support-compat-26.0.0-runtime.jar (com.android.support:support-compat:26.0.0)
需要在需要在gradle.properties中添加代码：
android.useAndroidX=true
android.enableJetifier=true