参考链接 https://stackoverflow.com/questions/52845161/error-program-type-already-present-android-support-v4-app-fragmenttransitionco 主要原因: gradle 文件没有导入 support v4 包 implementation 'com.android.support:appcompat-v7:28.0.0' // 添加下面这句即可 implementation 'com.android.support:support-v4:28.0.0'