（它没有rc01）清单合并失败：属性application @ appComponentFactory value =（android.support.v4.app.CoreComponentFactory）

Question

it says manifest merger error though my manifest is actually right

This is my app module gradle dependency file

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    //noinspection GradleCompatible
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    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 'com.android.support:cardview-v7:28.0.0'
    implementation 'com.android.support:design:28.0.0'
    implementation 'com.google.firebase:firebase-core:17.0.0'
    implementation 'com.google.firebase:firebase-database:18.0.0'
    implementation 'com.firebaseui:firebase-ui-database:0.4.1'
    implementation 'com.android.support:recyclerview-v7:28.0.0'
}
apply plugin: 'com.google.gms.google-services'

This is the error

manifest merger failed : Attribute application@appComponentFactory value=(android.support.v4.app.CoreComponentFactory) from [com.android.support:support-compat:28.0.0-alpha3] AndroidManifest.xml:22:18-91 is also present at [androidx.core:core:1.0.0-alpha3] AndroidManifest.xml:22:18-86 value=(androidx.core.app.CoreComponentFactory). Suggestion: add 'tools:replace="android:appComponentFactory"'

Answer 1

Issue is related to AndroidX libraries. Migrate your support libraries to AndroidX. In AndroidStudio you can use the Refactor > Migrate to AndroidX menu to do this manually. Keep track of changes with a VCS (eg git) to see what happens.

Also you can do it manually by changing your gradle dependencies to:

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    //noinspection GradleCompatible
    implementation 'androidx.appcompat:appcompat:1.0.2'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.0'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0'
    implementation 'androidx.cardview:cardview:1.0.0'
    implementation 'com.google.android.material:material:1.0.0'
    implementation 'com.google.firebase:firebase-core:17.0.0'
    implementation 'com.google.firebase:firebase-database:18.0.0'
    implementation 'com.firebaseui:firebase-ui-database:0.4.1'
    implementation 'androidx.recyclerview:recyclerview:1.0.0'
}
apply plugin: 'com.google.gms.google-services'

Then, find all old dependency imports with new ones.

---

Putting these flags in your gradle.properties can fix some relative issues:

 android.enableJetifier=true android.useAndroidX=true