我想创建一个密钥库来签署应用程序，但每次我得到这个错误时说什么？

Question

出了什么问题： 评估项目 ':app' 时出现问题。

没有方法签名：java.lang.String.isNumber() 适用于参数类型：（整数）值：[1] 可能的解决方案：isNumber()、isInteger()

Answer 1

更改这些行

versionCode flutterVersionCode.isNumber(1)
versionName flutterVersionName "1.0"

到这里：

versionCode 1
versionName "1.0"

或者这个：

    versionCode flutterVersionCode.toInteger()
    versionName flutterVersionName

Answer 2

    def localProperties = new Properties()
def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def flutterRoot = localProperties.getProperty('flutter.sdk')
if (flutterRoot == null) {
    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}

apply plugin: 'com.android.application'
apply plugin: 'com.google.gms.google-services'
apply plugin: 'kotlin-android'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

android {
    compileSdkVersion 28

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    lintOptions {
        disable 'InvalidPackage'
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "com.example.quotes_of_fariha"
        minSdkVersion 16
        targetSdkVersion 28
        versionCode flutterVersionCode.isNumber(1)
        versionName flutterVersionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        multiDexEnabled true
    }

    buildTypes {
        release { 
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig signingConfigs.debug
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
    implementation 'com.android.support:multidex:1.0.3'
    implementation 'com.google.firebase:firebase-analytics:17.5.0'
    implementation 'com.google.firebase:firebase-firestore:21.6.0'

}