Java, Android, camerax programming. Error: cannot find symbol. symbol: class Builder

Question

I am try to take a picture with an Android smartphone by using the camerax libary from Android.
I am following their tutorial to capture images. First I need to initalize the ImageCapturer:

ImageCapture imageCapture =
new ImageCapture.Builder()
    .setTargetRotation(view.getDisplay().getRotation())
    .build();

cameraProvider.bindToLifecycle(lifecycleOwner, cameraSelector, imageCapture, imageAnalysis, preview);

The Problem is I a error message and can't execute the code:

    ImageCapture imageCapture = new ImageCapture.Builder().setTargetRotation(view.getDisplay().getRotation()).build();
                                                ^
  symbol:   class Builder

I included the dependencies for camerax in the gradle file:

apply plugin: 'com.android.application'

repositories {
    jcenter()
}

android {
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    compileSdkVersion 28
    buildToolsVersion "29.0.2"
    defaultConfig {
        applicationId "org.pytorch.digitrecognizer"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            debuggable true
        }
    }
}

dependencies {
    def camerax_version = '1.0.0-alpha06'
    implementation "androidx.camera:camera-core:${camerax_version}"
    implementation "androidx.camera:camera-camera2:${camerax_version}"
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'org.pytorch:pytorch_android:1.4.0'
    implementation 'org.pytorch:pytorch_android_torchvision:1.4.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
}

I don't know why it doesn't recognize the .builderI. I hope someone can help me ^^

Answer 1

You're using the alpha06 version of the camerax core artifact, building a use case using the use case's builder was introduced in version07 of camerax core. For alpha06, you had to write:

PreviewConfig previewConfig = new PreviewConfig.Builder().build();
Preview preview = new Preview(previewConfig);

With more recent versions (starting from alpha07), you use the use case's builder to initialize use cases.

Preview preview = new Preview.Builder().build();

FYI, the documentation you're using is using the beta01 version of camerax core, you might want to update to that instead of using alpha06.