Shared Transition Text

ChangeText.java

import android.animation.Animator;
import android.animation.ArgbEvaluator;
import android.animation.ValueAnimator;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.graphics.Rect;
import android.os.Parcelable;
import android.transition.Transition;
import android.transition.TransitionSet;
import android.transition.TransitionValues;
import android.util.AttributeSet;
import android.util.Log;
import android.util.Pair;
import android.util.TypedValue;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.List;


/**
 * Created by richard on 24/10/15.
 */
@SuppressLint("NewApi")
public class ChangeText extends Transition {


    private static final String PROPNAME_TEXTSIZE = "android:resizetext:textSize";
    private static final String PROPNAME_TEXTCOLOR = "android:resizetext:textColor";
    private static final String PROPNAME_TEXTPADDING = "android:resizetext:textPadding";
    private static final String KEY_TEXT_SIZES = "key_text_sizes";
    private static final String KEY_TEXT_COLORS = "key_text_colors";
    private static final String KEY_TEXT_PADDINGS = "key_text_padding";
    private static final String KEY_TEXT_NAMES = "key_text_names";

    private static final String TAG = ChangeText.class.getSimpleName();
    private List<String> keyNames;
    private float[] sizeValues;
    private int[] colorValues;
    private Rect[] paddingValues;
    private boolean enter;

    @Override
    public void captureStartValues(TransitionValues transitionValues) {
        captureValues(transitionValues, "start");
    }




    private void captureValues(TransitionValues transitionValues, String log) {
        View view = transitionValues.view;
        if (view.getVisibility() == View.GONE) {
            return;
        }




        int index = keyNames.indexOf(view.getTransitionName());
        if (index > -1) {

            Log.d(TAG,log+"direction = "+enter);

            float textSize = sizeValues[index];
            int textColor = colorValues[index];
            Rect padding = paddingValues[index];
            transitionValues.values.put(PROPNAME_TEXTSIZE, textSize);
            transitionValues.values.put(PROPNAME_TEXTCOLOR, textColor);
            transitionValues.values.put(PROPNAME_TEXTPADDING, padding);
        }
    }

    public ChangeText() {
        init();
    }


    public ChangeText(Context context, AttributeSet attrs) {

        super(context, attrs);
        init();
    }

    private void init() {
        addTarget(TextView.class);
    }

    @Override
    public Animator createAnimator(ViewGroup sceneRoot, TransitionValues startValues, TransitionValues endValues) {
        if (startValues == null || startValues.values.size() == 0) {
            return null;
        }

        final TextView textView = ((TextView) startValues.view);

        int fromColor = (int) startValues.values.get(PROPNAME_TEXTCOLOR);
        int toColor = textView.getTextColors().getDefaultColor();

        float fromSize = (float) startValues.values.get(PROPNAME_TEXTSIZE);
        float toSize = textView.getTextSize();

        Rect fromPadding = (Rect)startValues.values.get(PROPNAME_TEXTPADDING);
        Rect toPadding = paddingToRect(textView);


        if(!enter){
            fromColor = fromColor + toColor;
            toColor = fromColor - toColor;
            fromColor = fromColor - toColor;

            fromSize = fromSize + toSize;
            toSize = fromSize - toSize;
            fromSize = fromSize - toSize;

            Rect temp = new Rect(toPadding);
            toPadding = fromPadding;
            fromPadding = temp;
        }

        final Rect finalFromPadding = fromPadding;
        final Rect finalToPadding = toPadding;


        final float finalFromSize = fromSize;
        final float finalToSize = toSize;



        ValueAnimator animator = ValueAnimator.ofObject(new ArgbEvaluator(),
                fromColor, toColor);
        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                Object value = animation.getAnimatedValue();
                float fraction = animation.getAnimatedFraction();
                textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, fracturedValue(fraction, finalFromSize, finalToSize));
                textView.setPadding(fracturedValue(fraction, finalFromPadding.left, finalToPadding.left), fracturedValue(fraction, finalFromPadding.top, finalToPadding.top), fracturedValue(fraction, finalFromPadding.right, finalToPadding.right), fracturedValue(fraction, finalFromPadding.bottom, finalToPadding.bottom));

                if (null != value) {
                    textView.setTextColor((Integer) value);
                }
            }
        });


        return animator;
    }

    private static Rect paddingToRect(TextView textView) {
        return new Rect(textView.getPaddingLeft(),textView.getPaddingTop(),textView.getPaddingRight(),textView.getPaddingBottom());
    }

    private static float fracturedValue(float fraction, float from, float to) {
        return from + ((to-from)*fraction);
    }

    private static int fracturedValue(float fraction, int from, int to) {
        return (int) fracturedValue(fraction,(float)from,(float)to);
    }

    @Override
    public void captureEndValues(TransitionValues transitionValues) {
        captureValues(transitionValues, "end");
    }

    public static void intent(Intent intent, View sharedView, String sharedElementName) {

        intent(intent, new Pair<View, String>(sharedView, sharedElementName));

    }

    public static void intent(Intent intent, Pair<View, String>... sharedElements) {

        float[] sizeArray = new float[sharedElements.length];
        int[] colorArray = new int[sharedElements.length];
        Rect[] paddingArray = new Rect[sharedElements.length];
        String[] keyArray = new String[sharedElements.length];
        boolean hasValue = false;

        int index = 0;
        for (Pair<View, String> sharedElement : sharedElements) {
            View view = sharedElement.first;
            if (view instanceof TextView) {
                TextView textView = ((TextView) sharedElement.first);
                hasValue = true;
                sizeArray[index] = textView.getTextSize();
                colorArray[index] = textView.getTextColors().getDefaultColor();
                paddingArray[index] = paddingToRect(textView);
                keyArray[index] = sharedElement.second;


            }
            index++;

        }

        if (hasValue) {
            intent.putExtra(KEY_TEXT_SIZES, sizeArray);
            intent.putExtra(KEY_TEXT_COLORS, colorArray);
            intent.putExtra(KEY_TEXT_PADDINGS,paddingArray);
            intent.putExtra(KEY_TEXT_NAMES, keyArray);
        }
    }

    public static <T extends Parcelable> T[] getParcelableArray(Intent bundle, String key, Class<T[]> type) {
        Parcelable[] value = bundle.getParcelableArrayExtra(key);
        if (value == null) {
            return null;
        }
        Object copy = Array.newInstance(type.getComponentType(), value.length);
        System.arraycopy(value, 0, copy, 0, value.length);
        return (T[]) copy;
    }



    public static void setup(Activity activity) {
        Intent intent = activity.getIntent();
        
        if (intent.hasExtra(KEY_TEXT_NAMES)) {

            Transition transitionEnter = activity.getWindow().getSharedElementEnterTransition();
            Transition transitionExit = activity.getWindow().getSharedElementReturnTransition();
            
            float[] sizeValues = intent.getFloatArrayExtra(KEY_TEXT_SIZES);
            int[] colorValues = intent.getIntArrayExtra(KEY_TEXT_COLORS);
            Rect[] paddingValues = getParcelableArray(intent,KEY_TEXT_PADDINGS,Rect[].class);
            List<String> keyNames = Arrays.asList(intent.getStringArrayExtra(KEY_TEXT_NAMES));

            setupValues(keyNames, sizeValues, colorValues, paddingValues,transitionEnter, true);
            setupValues(keyNames, sizeValues, colorValues, paddingValues,transitionExit, false);

        }
    }

    private static void setupValues(List<String> keyNames, float[] sizeValues, int[] colorValues, Rect[] paddingValues, Transition transition, boolean enter) {
        if (transition != null) {


            ChangeText changeTextTransition = null;


            if (transition instanceof TransitionSet) {
                TransitionSet set = (TransitionSet) transition;
                for (int i = 0; i < set.getTransitionCount(); i++) {
                    Transition transitionInSet = set.getTransitionAt(i);
                    if (transitionInSet instanceof ChangeText) {
                        changeTextTransition = (ChangeText) transitionInSet;
                        break;
                    }


                }
            } else if (!(transition instanceof ChangeText)) {
                return;
            } else {
                changeTextTransition = (ChangeText) transition;
            }
            if (changeTextTransition != null) {
                changeTextTransition.setValues(keyNames, sizeValues, colorValues, paddingValues,enter);
            }
        }
    }

    private void setValues(List<String> keyNames, float[] sizeValues, int[] colorValues, Rect[] paddingValues, boolean enter) {
        this.keyNames = keyNames;
        this.sizeValues = sizeValues;
        this.colorValues = colorValues;
        this.paddingValues = paddingValues;
        this.enter = enter;
    }
}

curve.xml

<?xml version="1.0" encoding="utf-8"?>
<transitionSet
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:duration="450">
    <changeBounds  />
    <changeTransform/>
    <changeClipBounds/>
    <changeImageTransform/>
    <transition class="com.yourpackage.transition.ChangeText"  />
    <arcMotion android:minimumHorizontalAngle="50" android:minimumVerticalAngle="50" />
</transitionSet>

DetailActivity.java

public static void startActivity(Activity activity, int intentParamterOrSomething, View sharedView){
  Intent intent = new Intent(activity, DetailActivity.class);
  intent.putExtra(EXTRA_WHATEVER, intentParamterOrSomething);
  Bundle bundle  = null;
  
  if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
  	bundle = ActivityOptionsCompat.makeSceneTransitionAnimation(activity, sharedView, sharedView.getTransitionName()).toBundle();
  	ChangeText.intent(intent, sharedView, sharedView.getTransitionName());
  }
  ActivityCompat.startActivity(activity, intent, bundle);
}

@Override
protected void onCreate(Bundle savedInstanceState) {
  ...
  
  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            getWindow().setSharedElementEnterTransition(TransitionInflater.from(this)
                    .inflateTransition(R.transition.curve));
            getWindow().setSharedElementReturnTransition(TransitionInflater.from(this)
                    .inflateTransition(R.transition.curve));
            ChangeText.setup(this);
  }
 ... 
}