Invoke-customs are only supported starting with Android,Static interface methods are only supported

問題1
Invoke-customs are only supported starting with Android O (–min-api 26)
Message{kind=ERROR, text=Invoke-customs are only supported starting with Android O (–min-api 26), sources=[Unknown source file], tool name=Optional.of(D8)}

問題2
Static interface methods are only supported starting with Android N (–min-api 24): org.webrtc.EglBase org.webrtc.EglBase.create()
Message{kind=ERROR, text=Static interface methods are only supported starting with Android N (–min-api 24): org.webrtc.EglBase org.webrtc.EglBase.create(), sources=[Unknown source file], tool name=Optional.of(D8)}

問題3
錯誤: -source 1.7 中不支持 lambda 表達式
(請使用 -source 8 或更高版本以啓用 lambda 表達式)

這3個問題都是因爲沒有指定jdk 1.8而產生的。

解決方案：
在主工程的build.gradle中添加以下代碼，指定jdk版本爲1.8

android {
    ......
    //指定jdk版本
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}