要实现ARCore Sceneform ViewRenderable随机旋转图像的角度，可以使用以下代码示例：

import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import androidx.appcompat.app.AppCompatActivity;

import com.google.ar.core.Anchor;
import com.google.ar.core.Frame;
import com.google.ar.core.Plane;
import com.google.ar.core.Pose;
import com.google.ar.core.Session;
import com.google.ar.core.TrackingState;
import com.google.ar.sceneform.AnchorNode;
import com.google.ar.sceneform.ArSceneView;
import com.google.ar.sceneform.rendering.ModelRenderable;
import com.google.ar.sceneform.rendering.Renderable;
import com.google.ar.sceneform.rendering.ViewRenderable;
import com.google.ar.sceneform.ux.ArFragment;
import com.google.ar.sceneform.ux.TransformableNode;

import java.util.Random;

public class MainActivity extends AppCompatActivity {

    private ArFragment arFragment;
    private Button addButton;
    private boolean isPlaced = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        arFragment = (ArFragment) getSupportFragmentManager().findFragmentById(R.id.arFragment);
        addButton = findViewById(R.id.addButton);

        addButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (!isPlaced) {
                    placeObject();
                    isPlaced = true;
                }
            }
        });

        arFragment.getArSceneView().getScene().addOnUpdateListener(frameTime -> {
            if (isPlaced) {
                Frame frame = arFragment.getArSceneView().getArFrame();
                if (frame != null) {
                    Session session = arFragment.getArSceneView().getSession();
                    if (session != null && session.isTracking() && session.getTrackingState() == TrackingState.TRACKING) {
                        for (Plane plane : session.getAllTrackables(Plane.class)) {
                            if (plane.getType() == Plane.Type.HORIZONTAL_UPWARD_FACING && plane.getTrackingState() == TrackingState.TRACKING) {
                                arFragment.getPlaneDiscoveryController().hide();
                                break;
                            }
                        }

                        for (Anchor anchor : session.getAllAnchors()) {
                            Anchor.State anchorState = anchor.getTrackingState();
                            if (anchorState == Anchor.State.TRACKING) {
                                adjustObjectRotation(anchor);
                                break;
                            }
                        }
                    }
                }
            }
        });
    }

    private void placeObject() {
        // Replace "model.sfb" with your 3D model file
        ModelRenderable.builder()
                .setSource(this, R.raw.model)
                .build()
                .thenAccept(renderable -> {
                    Anchor anchor = arFragment.getArSceneView().getSession().createAnchor(Pose.IDENTITY);
                    AnchorNode anchorNode = new AnchorNode(anchor);
                    anchorNode.setParent(arFragment.getArSceneView().getScene());
                    TransformableNode objectNode = new TransformableNode(arFragment.getTransformationSystem());
                    objectNode.setParent(anchorNode);
                    objectNode.setRenderable(renderable);
                    objectNode.select();
                });
    }

    private void adjustObjectRotation(Anchor anchor) {
        float randomAngle = new Random().nextFloat() * 360;
        AnchorNode anchorNode = new AnchorNode(anchor);
        anchorNode.setParent(arFragment.getArSceneView().getScene());
        anchorNode.setLocalRotation(Quaternion.axisAngle(new Vector3(0, 1f, 0), randomAngle));
    }
}

在这个示例中，我们首先创建了一个ArFragment和一个按钮Button。当按钮被点击时，我们调用placeObject()方法来在AR场景中放置一个3D模型。

在arFragment.getArSceneView().getScene().addOnUpdateListener()中，我们监听AR场景的更新，在每一帧中检查AR会话的状态。如果3D模型已经放置，我们遍历场景中的所有锚点，找到跟踪状态为TRACKING的锚点，并调用adjustObjectRotation()方法来随机旋转模型的角度。

在adjustObjectRotation()方法中，我们通过Quaternion.axisAngle()方法来创建一个绕Y轴旋转的四元数，旋转角度为0到360度之间的随机值。然后我们将这个旋转应用到锚点上，使得模型随机旋转。

请注意，在示例代码中，我们使用了一个名为model.sfb的3D模型文件。你需要将该文件替换为自己