Not able to sync dependency in build.gradle in flutter

That is the problem with gradle sync of Android project, not with Flutter dependencies.

In your build.gradle of your module (for example android/app/build.gradle of your Flutter project) add:

implementation 'com.google.android.gms:play-services-vision:10.+'

in dependencies as bellow:

dependencies {
    implementation 'com.google.android.gms:play-services-vision:10.+'
    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'
}

Then open terminal, cd to android folder of your flutter project and run:

$./gradlew build

After that you will be able import com.google.android.gms... in your Java class.

If you're using Android Studio for Flutter development, right click on the android folder in your Flutter project. Select "Flutter" -> "Open Android Module in Android Studio".

Or

Simply start Android Studio and open the Android (sub)project directly.

In any case, once the Android project is opened in Android Studio, you can make changes in your build.gradle. The editor will tell you to sync. Otherwise simply execute a build. Afterwards you will be able to import use your Android classes.

i know i am late but let me suggest the way as per i done and it's working , if it helps to someone

1. Open android studio flutter project
2. Go to file
3. Click on setting
4. Search for "Flutter"
5. at bottom of that view there is an experiments section do check that both checkbox

after doing this add any dependencies in android gradle and go to file and click on "Sync with file system" and you are done , please check the below screenshot to do check the experiments item

Go to android folder of your flutter project and then

open it in terminal by right clicking on that folder

then try to run below command

gradlew build