Loading dialog that shows a flip animation using a random list of icons

card_flip_right_in.xml

<set xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- Before rotating, immediately set the alpha to 0. -->
    <objectAnimator
        android:valueFrom="1.0"
        android:valueTo="0.0"
        android:propertyName="alpha"
        android:duration="0" />

    <!-- Rotate. -->
    <objectAnimator
        android:valueFrom="180"
        android:valueTo="0"
        android:propertyName="rotationY"
        android:interpolator="@android:interpolator/accelerate_decelerate"
        android:duration="@integer/card_flip_time_full" />

    <!-- Half-way through the rotation (see startOffset), set the alpha to 1. -->
    <objectAnimator
        android:valueFrom="0.0"
        android:valueTo="1.0"
        android:propertyName="alpha"
        android:startOffset="@integer/card_flip_time_half"
        android:duration="1" />
</set>

card_flip_right_out.xml

<set xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- Rotate. -->
    <objectAnimator
        android:valueFrom="0"
        android:valueTo="-180"
        android:propertyName="rotationY"
        android:interpolator="@android:interpolator/accelerate_decelerate"
        android:duration="@integer/card_flip_time_full" />

    <!-- Half-way through the rotation (see startOffset), set the alpha to 0. -->
    <objectAnimator
        android:valueFrom="1.0"
        android:valueTo="0.0"
        android:propertyName="alpha"
        android:startOffset="@integer/card_flip_time_half"
        android:duration="1" />
</set>

CustomDialogFragment.java

package com.example.android.animationsdemo;

import android.animation.Animator;
import android.animation.AnimatorInflater;
import android.animation.AnimatorListenerAdapter;
import android.animation.AnimatorSet;
import android.app.Dialog;
import android.app.DialogFragment;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.widget.ImageView;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

public class CustomDialogFragment extends DialogFragment {

    /**
     * ImageViews for the animation (front, back)
     */
    private ImageView vImageFront;
    private ImageView vImageBack;

    /**
     * Flag for continuous animation
     */
    private boolean mContinueAnimation;

    /**
     * Flag for displayed face
     */
    private boolean mFrontVisible;

    /**
     * Array with Image resources (this implementation assumes that we have at least two resources)
     */
    private List<Integer> mImageResources = new ArrayList<>(
            Arrays.asList(
                    R.drawable.bearish,
                    R.drawable.card_in_use,
                    R.drawable.money_bag,
                    R.drawable.self_service_kiosk,
                    R.drawable.shop,
                    R.drawable.shopping_cart
            )

    );

    /**
     * Iterator over the drawable list
     */
    private Iterator<Integer> mImagesIterator;

    /**
     * Current drawable id
     */
    private int mCurrentDrawable;

    public CustomDialogFragment() {
        // Required empty public constructor
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment_custom_dialog, container, false);
        vImageFront = (ImageView) v.findViewById(R.id.image_front);
        vImageBack = (ImageView) v.findViewById(R.id.image_back);

        mContinueAnimation = true;
        setUpIterator();

        vImageFront.setImageResource(mImagesIterator.next());
        vImageBack.setImageResource(mImagesIterator.next());

        startFlipAnimation(vImageBack, vImageFront);

        // Inflate the layout for this fragment
        return v;
    }

    /**
     * The system calls this only when creating the layout in a dialog.
     */
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // The only reason you might override this method when using onCreateView() is
        // to modify any dialog characteristics. For example, the dialog includes a
        // title by default, but your custom layout might not need it. So here you can
        // remove the dialog title, but you must call the superclass to get the Dialog.
        Dialog dialog = super.onCreateDialog(savedInstanceState);
        dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
        return dialog;
    }

    @Override
    public void onDismiss(DialogInterface dialog) {
        this.mContinueAnimation = false;
        super.onDismiss(dialog);
    }

    private AnimatorSet getShowAnimation() {
        return (AnimatorSet) AnimatorInflater.loadAnimator(getActivity(),
                R.animator.card_flip_right_in);
    }

    private AnimatorSet getHideAnimation() {
        return (AnimatorSet) AnimatorInflater.loadAnimator(getActivity(),
                R.animator.card_flip_right_out);
    }

    private void startFlipAnimation(Object A, Object B) {
        if(!mContinueAnimation) {
            return;
        }

        AnimatorSet showAnimation = getShowAnimation();
        showAnimation.setTarget(A);
        AnimatorSet hideAnimation = getHideAnimation();
        hideAnimation.setTarget(B);
        AnimatorSet flipAnimation = new AnimatorSet();
        flipAnimation.playTogether(showAnimation, hideAnimation);
        flipAnimation.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationEnd(Animator animation) {
                super.onAnimationEnd(animation);

                mCurrentDrawable = mImagesIterator.next();

                if (mFrontVisible) {
                    vImageBack.setImageResource(mCurrentDrawable);
                    startFlipAnimation(vImageBack, vImageFront);
                } else {
                    vImageFront.setImageResource(mCurrentDrawable);
                    startFlipAnimation(vImageFront, vImageBack);
                }

                if (!mImagesIterator.hasNext()) {
                    setUpIterator();
                }

                mFrontVisible = !mFrontVisible;
            }
        });
        flipAnimation.start();
    }

    private void setUpIterator() {
        Collections.shuffle(mImageResources);
        this.mImagesIterator = mImageResources.iterator();
        // Prevents the same image is displayed twice in a row
        if(mCurrentDrawable == mImageResources.get(0)) { // If next image is the same as current
            this.mImagesIterator.next(); // Advance the iterator
        }
    }

}

DialogFlipActivity.java

package com.example.android.animationsdemo;

import android.app.Activity;
import android.app.FragmentManager;
import android.os.Bundle;
import android.view.View;

public class DialogFlipActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_dialog_flip);
        findViewById(R.id.text).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                showDialog();
            }
        });
    }

    private void showDialog() {
        FragmentManager fragmentManager = getFragmentManager();
        CustomDialogFragment newFragment = new CustomDialogFragment();
        newFragment.show(fragmentManager, "DialogFragment");
    }
}

integers.xml

<resources>
    <integer name="card_flip_time_full">1000</integer>
    <integer name="card_flip_time_half">500</integer>
</resources>