A resizable textview with animation that depends on screen width and decreases in relation to stepTextSize attribute

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:android="http://schemas.android.com/apk/res/android">

    <declare-styleable name="ResizableTextView">
        <attr name="minTextSize" format="dimension" />
        <attr name="maxTextSize" format="dimension" />
        <attr name="stepTextSize" format="dimension" />
    </declare-styleable>

</resources>

layout.xml

     <ResizableTextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="bottom|right"
            android:enabled="false"
            android:textAlignment="textEnd"
            android:maxLines="1"
            minTextSize="36sp"
            maxTextSize="64sp"
            stepTextSize="8sp"/>

ResizableTextView.java

public class ResizableTextView extends TextView {

    private final float mMaximumTextSize;
    private final float mMinimumTextSize;
    private final float mStepTextSize;

    private final Paint mTempPaint = new TextPaint();
    private final Rect mTempRect = new Rect();

    private int mWidthConstraint = -1;
    private OnTextSizeChangeListener mOnTextSizeChangeListener;

    public ResizableTextView(Context context) {
        this(context, null);
    }

    public ResizableTextView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }


    public ResizableTextView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        final TypedArray a = context.obtainStyledAttributes(
                attrs, R.styleable.ResizableTextView, defStyle, 0);
        mMaximumTextSize = a.getDimension(
                R.styleable.ResizableTextView_maxTextSize, getTextSize());
        mMinimumTextSize = a.getDimension(
                R.styleable.ResizableTextView_minTextSize, getTextSize());
        mStepTextSize = a.getDimension(R.styleable.ResizableTextView_stepTextSize,
                (mMaximumTextSize - mMinimumTextSize) / 3);

        a.recycle();

        if (isFocusable()) {
            setMovementMethod(ScrollingMovementMethod.getInstance());
        }

        setTextSize(TypedValue.COMPLEX_UNIT_PX, mMaximumTextSize);
        setMinHeight(getLineHeight() + getCompoundPaddingBottom() + getCompoundPaddingTop());
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        mWidthConstraint =
                MeasureSpec.getSize(widthMeasureSpec) - getPaddingLeft() - getPaddingRight();
        setTextSize(TypedValue.COMPLEX_UNIT_PX, getVariableTextSize(getText().toString()));
    }

    @Override
    protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
        super.onTextChanged(text, start, lengthBefore, lengthAfter);
        setTextSize(TypedValue.COMPLEX_UNIT_PX, getVariableTextSize(text.toString()));
    }

    @Override
    public void setTextSize(int unit, float size) {
        final float oldTextSize = getTextSize();
        super.setTextSize(unit, size);

        if (mOnTextSizeChangeListener != null && getTextSize() != oldTextSize) {
            mOnTextSizeChangeListener.onTextSizeChanged(this, oldTextSize);
        }
    }

    public void setOnTextSizeChangeListener(OnTextSizeChangeListener listener) {
        mOnTextSizeChangeListener = listener;
    }

    public float getVariableTextSize(String text) {
        if (mWidthConstraint < 0 || mMaximumTextSize <= mMinimumTextSize) {
            return getTextSize();
        }

        mTempPaint.set(getPaint());

        float lastFitTextSize = mMinimumTextSize;
        while (lastFitTextSize < mMaximumTextSize) {
            final float nextSize = Math.min(lastFitTextSize + mStepTextSize, mMaximumTextSize);
            mTempPaint.setTextSize(nextSize);
            if (mTempPaint.measureText(text) > mWidthConstraint) {
                break;
            } else {
                lastFitTextSize = nextSize;
            }
        }

        return lastFitTextSize;
    }

    @Override
    public int getCompoundPaddingTop() {
        getPaint().getTextBounds("H", 0, 1, mTempRect);

        final Paint.FontMetricsInt fontMetrics = getPaint().getFontMetricsInt();
        final int paddingOffset = -(fontMetrics.ascent + mTempRect.height());
        return super.getCompoundPaddingTop() - Math.min(getPaddingTop(), paddingOffset);
    }

    @Override
    public int getCompoundPaddingBottom() {
        final Paint.FontMetricsInt fontMetrics = getPaint().getFontMetricsInt();
        return super.getCompoundPaddingBottom() - Math.min(getPaddingBottom(), fontMetrics.descent);
    }

    public interface OnTextSizeChangeListener {
        void onTextSizeChanged(TextView textView, float oldSize);
    }
}

ResizableTextViewListenerImpl.java

    @Override
    public void onTextSizeChanged(TextView textView, float oldSize) {
        final float textScale = oldSize / textView.getTextSize();
        final float translationX = (1.0f - textScale) *
                (textView.getWidth() / 2.0f - textView.getPaddingEnd());
        final float translationY = (1.0f - textScale) *
                (textView.getHeight() / 2.0f - textView.getPaddingBottom());

        final AnimatorSet animatorSet = new AnimatorSet();
        animatorSet.playTogether(
                ObjectAnimator.ofFloat(textView, View.SCALE_X, textScale, 1.0f),
                ObjectAnimator.ofFloat(textView, View.SCALE_Y, textScale, 1.0f),
                ObjectAnimator.ofFloat(textView, View.TRANSLATION_X, translationX, 0.0f),
                ObjectAnimator.ofFloat(textView, View.TRANSLATION_Y, translationY, 0.0f));
        animatorSet.setDuration(getResources().getInteger(android.R.integer.config_mediumAnimTime));
        animatorSet.setInterpolator(new AccelerateDecelerateInterpolator());
        animatorSet.start();
    }