QRCode/app/build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28

    defaultConfig {
        applicationId "me.yoqi.qrcode"
        minSdkVersion 14
        targetSdkVersion 28
    }

    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-project.txt'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
//    implementation 'com.android.support:appcompat-v7:21.0.3'
    implementation 'com.android.support:appcompat-v7:28.0.0'
//    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
//    implementation files('libs/zxing.jar')
}