Program type already present: android.support.v4.app.backstackrecord$Op

Program type already present:android.support.v4.app.backstackrecord$Op

（程序类型已经存在：android.support.v4.app.backstackrecord$Op）

调试过程中如果出现上述错误 

最好的解决办法是把build.gradle文件中的下面部分：

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:27.1.1'
    implementation 'com.android.support:recyclerview-v7:27.1.1'
    implementation 'com.android.support:design:27.1.1'
    implementation 'com.squareup.picasso:picasso:2.5.2'
    testCompile 'junit:junit:4.12'
    implementation 'com.google.code.gson:gson:2.2.4'
    implementation 'com.android.support.constraint:constraint-layout:1.1.1'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation files('libs/okhttp-3.2.0.jar')


    
}

修改为一样 27.1.1

亲测可以解决这个异常！