practical-android | Source code for 'Practical Android ' by Mark Wickham | Android library

The most probably is that the version of the gradle build tools of these projects is not compatible with the build tools that your Android Studio supports..

So before opening any of these projects (to keep them unmodified by Android Studio), you can migrate them to the gradle version that already you've on android-studio. To do that you can use a text editor to change:

1. In myAppName\gradle\wrapper\gradle-wrapper.properties file, in the line distributionUrl=https\://services.gradle.org/distributions/gradle-6.7.1-bin.zip: change to the gradle version you've (so you need to change this number in your example 6.7.1)

You can know the current gradle version(s) of Android studio from C:/Users/myUserName/.gradle/wrapper/dists/

1. In myAppName\build.gradle you need to change the gradle plugin version to be matched with the gradle distribution version you've from step no.1. Documentation table that lists which version of Gradle is required for each version of the Android Gradle plugin.

UPDATE

Please follow below procedure.. it is tedious but works:

1. Create a brand new project that has a package name that is the same as that of your project.

2. Copy src, lib, raw .. or any assets folders under /app of your project into the /app of the brand new project ..

3. Remove the themes.xml files

4. Copy dependency from \app\build.gradle to the new project & replace compile with implementation, and testCompile with testImplementation

I did a test on one of the apps emailing app and it runs.