Error gradle when run about flutter_ui_challenges HOT 6 CLOSED

D:\Flutter Tutorials\31_May\flutter_ui_challenges-master>flutter run
Using hardware rendering with device Android SDK built for x86. If you get graphics artifacts, consider enabling software
rendering with "--enable-software-rendering".
Launching lib/main.dart on Android SDK built for x86 in debug mode...
Initializing gradle...                                              3.1s
Resolving dependencies...
* Error running Gradle:
ProcessException: Process "D:\Flutter Tutorials\31_May\flutter_ui_challenges-master\android\gradlew.bat" exited abnormally:

FAILURE: Build failed with an exception.

* Where:
Build file 'D:\Flutter Tutorials\31_May\flutter_ui_challenges-master\android\app\build.gradle' line: 52

* What went wrong:
A problem occurred evaluating project ':app'.
> path may not be null or empty string. path='null'

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan
to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 34s
  Command: D:\Flutter Tutorials\31_May\flutter_ui_challenges-master\android\gradlew.bat app:properties

Please review your Gradle project setup in the android/ folder.

D:\Flutter Tutorials\31_May\flutter_ui_challenges-master>flutter doctor
Waiting for another flutter command to release the startup lock...
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, v1.2.1, on Microsoft Windows [Version 6.1.7601], locale en-US)
[√] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
[√] Android Studio (version 3.3)
[√] Connected device (1 available)

• No issues found!

D:\Flutter Tutorials\31_May\flutter_ui_challenges-master>flutter doctor -v
[√] Flutter (Channel stable, v1.2.1, on Microsoft Windows [Version 6.1.7601], locale en-US)
    • Flutter version 1.2.1 at D:\flutter
    • Framework revision 8661d8aecd (4 months ago), 2019-02-14 19:19:53 -0800
    • Engine revision 3757390fa4
    • Dart version 2.1.2 (build 2.1.2-dev.0.0 0a7dcf17eb)

[√] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
    • Android SDK at C:\Users\Saitech\AppData\Local\Android\sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-28, build-tools 28.0.3
    • Java binary at: D:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1248-b01)
    • All Android licenses accepted.

[√] Android Studio (version 3.3)
    • Android Studio at D:\Program Files\Android\Android Studio
    • Flutter plugin version 33.3.1
    • Dart plugin version 182.5215
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1248-b01)

[√] Connected device (1 available)
    • Android SDK built for x86 • emulator-5554 • android-x86 • Android 9 (API 28) (emulator)

• No issues found!

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 from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

android {
    compileSdkVersion 28

    lintOptions {
        disable 'InvalidPackage'
    }

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

    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 {
    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'
}