What is "Program type already present"?

Question

When i try to build my project.i got this error

Program type already present: android.support.v4.accessibilityservice.AccessibilityServiceInfoCompat Message{kind=ERROR, text=Program type already present: android.support.v4.accessibilityservice.AccessibilityServiceInfoCompat, sources=[Unknown source file], tool name=Optional.of(D8)}

i also to find solution in stack overflow but it didn't help.here is my build.gradle file

    apply plugin: 'com.android.application'android {
compileSdkVersion 28
defaultConfig {
    applicationId "com.example.hassan.qrscan"
    minSdkVersion 18
    targetSdkVersion 28
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}}dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
//noinspection GradleCompatible
implementation 'com.android.support:appcompat-v7:28.0.0-alpha1'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
implementation 'me.dm7.barcodescanner:zxing:1.9'
implementation 'com.journeyapps:zxing-android-embedded:3.0.2@aar'
implementation 'com.android.support:design:28.0.0'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'}

Answer 1

The Program Type Already Present error Raised whenever your project has the repeating libraries or same library with a different version. You can Check the Dependancies Graph by running

gradlew -q dependencies

or

gradle -q dependencies

(Required the Gradle in your class path)

Just sort out the repeating libraries, remove repeating one and error will go away.

Answer 2

I solve this problem by using same version of appcompact and design

 implementation 'com.android.support:appcompat-v7:28.0.0-alpha1'
 implementation 'com.android.support:design:28.0.0-alpha1'

but now i got this error

Program type already present: android.support.v4.app.FragmentTransitionCompat21$1

Answer 3

 implementation 'com.android.support:appcompat-v7:28.0.0-alpha1'

downgrade the version of dependency to

 implementation 'com.android.support:appcompat-v7:27.1.0'

and also add the design dependency

 implementation 'com.android.support:design:27.1.0'

check it once this works for me