AutoResizeTextView.java

package com.thoughtmonkeys.pitstop;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.RectF;
import android.os.Build;
import android.text.Layout.Alignment;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.util.SparseIntArray;
import android.util.TypedValue;
import android.widget.TextView;

public class AutoResizeTextView extends TextView {
    private interface SizeTester {
        /**
         *
         * @param suggestedSize
         *            Size of text to be tested
         * @param availableSpace
         *            available space in which text must fit
         * @return an integer < 0 if after applying {@code suggestedSize} to
         *         text, it takes less space than {@code availableSpace}, > 0
         *         otherwise
         */
        public int onTestSize(int suggestedSize, RectF availableSpace);
    }

    private RectF mTextRect = new RectF();

    private RectF mAvailableSpaceRect;

    private SparseIntArray mTextCachedSizes;

    private TextPaint mPaint;

    private float mMaxTextSize;

    private float mSpacingMult = 1.0f;

    private float mSpacingAdd = 0.0f;

    private float mMinTextSize = 10;

    private int mWidthLimit;

    private static final int NO_LINE_LIMIT = -1;
    private int mMaxLines;

    private boolean mEnableSizeCache = true;
    private boolean mInitiallized;

    public AutoResizeTextView(Context context) {
        super(context);
        initialize();
    }

    public AutoResizeTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initialize();
    }

    public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initialize();
    }

    private void initialize() {
        mPaint = new TextPaint(getPaint());
        mMaxTextSize = getTextSize();
        mAvailableSpaceRect = new RectF();
        mTextCachedSizes = new SparseIntArray();
        if (mMaxLines == 0) {
            // no value was assigned during construction
            mMaxLines = NO_LINE_LIMIT;
        }
        mInitiallized = true;
    }

    @Override
    public void setText(final CharSequence text, BufferType type) {
        super.setText(text, type);
        adjustTextSize(text.toString());
    }

    @Override
    public void setTextSize(float size) {
        mMaxTextSize = size;
        mTextCachedSizes.clear();
        adjustTextSize(getText().toString());
    }

    @Override
    public void setMaxLines(int maxlines) {
        super.setMaxLines(maxlines);
        mMaxLines = maxlines;
        reAdjust();
    }

    public int getMaxLines() {
        return mMaxLines;
    }

    @Override
    public void setSingleLine() {
        super.setSingleLine();
        mMaxLines = 1;
        reAdjust();
    }

    @Override
    public void setSingleLine(boolean singleLine) {
        super.setSingleLine(singleLine);
        if (singleLine) {
            mMaxLines = 1;
        } else {
            mMaxLines = NO_LINE_LIMIT;
        }
        reAdjust();
    }

    @Override
    public void setLines(int lines) {
        super.setLines(lines);
        mMaxLines = lines;
        reAdjust();
    }

    @Override
    public void setTextSize(int unit, float size) {
        Context c = getContext();
        Resources r;

        if (c == null)
            r = Resources.getSystem();
        else
            r = c.getResources();
        mMaxTextSize = TypedValue.applyDimension(unit, size,
                r.getDisplayMetrics());
        mTextCachedSizes.clear();
        adjustTextSize(getText().toString());
    }

    @Override
    public void setLineSpacing(float add, float mult) {
        super.setLineSpacing(add, mult);
        mSpacingMult = mult;
        mSpacingAdd = add;
    }

    /**
     * Set the lower text size limit and invalidate the view
     *
     * @param minTextSize
     */
    public void setMinTextSize(float minTextSize) {
        mMinTextSize = minTextSize;
        reAdjust();
    }

    public void reAdjust() {
        adjustTextSize(getText().toString());
    }

    private void adjustTextSize(final String text) {
        if (!mInitiallized) {
            return;
        }
        int heightLimit = getMeasuredHeight() - getCompoundPaddingBottom() - getCompoundPaddingTop();
        mWidthLimit = getMeasuredWidth() - getCompoundPaddingLeft() - getCompoundPaddingRight();

        mAvailableSpaceRect.right = mWidthLimit;
        mAvailableSpaceRect.bottom = heightLimit;

        int maxTextSplits = text.split(" ").length;
        AutoResizeTextView.super.setMaxLines(Math.min(maxTextSplits, mMaxLines));

        super.setTextSize(
                TypedValue.COMPLEX_UNIT_SP,
                binarySearch((int) mMinTextSize, (int) mMaxTextSize,
                        mSizeTester, mAvailableSpaceRect));
    }

    private final SizeTester mSizeTester = new SizeTester() {
        @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
        @Override
        public int onTestSize(int suggestedSize, RectF availableSPace) {
            mPaint.setTextSize(suggestedSize);
            String text = getText().toString();
            boolean singleline = getMaxLines() == 1;
            if (singleline) {
                mTextRect.bottom = mPaint.getFontSpacing();
                mTextRect.right = mPaint.measureText(text);
            } else {
                StaticLayout layout = new StaticLayout(text, mPaint,
                        mWidthLimit, Alignment.ALIGN_NORMAL, mSpacingMult,
                        mSpacingAdd, true);
                // return early if we have more lines
                if (getMaxLines() != NO_LINE_LIMIT
                        && layout.getLineCount() > getMaxLines()) {
                    return 1;
                }
                mTextRect.bottom = layout.getHeight();
                int maxWidth = -1;
                for (int i = 0; i < layout.getLineCount(); i++) {
                    if (maxWidth < layout.getLineWidth(i)) {
                        maxWidth = (int) layout.getLineWidth(i);
                    }
                }
                mTextRect.right = maxWidth;
            }

            mTextRect.offsetTo(0, 0);
            if (availableSPace.contains(mTextRect)) {
                // may be too small, don't worry we will find the best match
                return -1;
            } else {
                // too big
                return 1;
            }
        }
    };

    /**
     * Enables or disables size caching, enabling it will improve performance
     * where you are animating a value inside TextView. This stores the font
     * size against getText().length() Be careful though while enabling it as 0
     * takes more space than 1 on some fonts and so on.
     *
     * @param enable
     *            enable font size caching
     */
    public void enableSizeCache(boolean enable) {
        mEnableSizeCache = enable;
        mTextCachedSizes.clear();
        adjustTextSize(getText().toString());
    }

    private int efficientTextSizeSearch(int start, int end,
                                        SizeTester sizeTester, RectF availableSpace) {
        if (!mEnableSizeCache) {
            return binarySearch(start, end, sizeTester, availableSpace);
        }
        String text = getText().toString();
        int key = text == null ? 0 : text.length();
        int size = mTextCachedSizes.get(key);
        if (size != 0) {
            return size;
        }
        size = binarySearch(start, end, sizeTester, availableSpace);
        mTextCachedSizes.put(key, size);
        return size;
    }

    private static int binarySearch(int start, int end, SizeTester sizeTester,
                                    RectF availableSpace) {
        int lastBest = start;
        int lo = start;
        int hi = end - 1;
        int mid = 0;
        while (lo <= hi) {
            mid = (lo + hi) >>> 1;
            int midValCmp = sizeTester.onTestSize(mid, availableSpace);
            if (midValCmp < 0) {
                lastBest = lo;
                lo = mid + 1;
            } else if (midValCmp > 0) {
                hi = mid - 1;
                lastBest = hi;
            } else {
                return mid;
            }
        }
        // make sure to return last best
        // this is what should always be returned
        return lastBest;

    }

    @Override
    protected void onTextChanged(final CharSequence text, final int start,
                                 final int before, final int after) {
        super.onTextChanged(text, start, before, after);
        reAdjust();
    }

    @Override
    protected void onSizeChanged(int width, int height, int oldwidth,
                                 int oldheight) {
        mTextCachedSizes.clear();
        super.onSizeChanged(width, height, oldwidth, oldheight);
        if (width != oldwidth || height != oldheight) {
            reAdjust();
        }
    }
}


///**
// *               DO WHAT YOU WANT TO PUBLIC LICENSE
// *                    Version 2, December 2004
// *
// * Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
// *
// * Everyone is permitted to copy and distribute verbatim or modified
// * copies of this license document, and changing it is allowed as long
// * as the name is changed.
// *
// *            DO WHAT YOU WANT TO PUBLIC LICENSE
// *   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
// *
// *  0. You just DO WHAT YOU WANT TO.
// */
//
//import android.content.Context;
//import android.text.Layout.Alignment;
//import android.text.StaticLayout;
//import android.text.TextPaint;
//import android.util.AttributeSet;
//import android.util.TypedValue;
//import android.widget.TextView;
//
///**
// * Text view that auto adjusts text size to fit within the view.
// * If the text size equals the minimum text size and still does not
// * fit, append with an ellipsis.
// *
// * @author Chase Colburn
// * @since Apr 4, 2011
// */
//public class AutoResizeTextView extends TextView {
//
//    // Minimum text size for this text view
//    public static final float MIN_TEXT_SIZE = 15;
//
//    // Interface for resize notifications
//    public interface OnTextResizeListener {
//        public void onTextResize(TextView textView, float oldSize, float newSize);
//    }
//
//    // Our ellipse string
//    private static final String mEllipsis = "...";
//
//    // Registered resize listener
//    private OnTextResizeListener mTextResizeListener;
//
//    // Flag for text and/or size changes to force a resize
//    private boolean mNeedsResize = false;
//
//    // Text size that is set from code. This acts as a starting point for resizing
//    private float mTextSize;
//
//    // Temporary upper bounds on the starting text size
//    private float mMaxTextSize = 20;
//
//    // Lower bounds for text size
//    private float mMinTextSize = MIN_TEXT_SIZE;
//
//    // Text view line spacing multiplier
//    private float mSpacingMult = 1.0f;
//
//    // Text view additional line spacing
//    private float mSpacingAdd = 0.0f;
//
//    // Add ellipsis to text that overflows at the smallest text size
//    private boolean mAddEllipsis = true;
//
//    // Default constructor override
//    public AutoResizeTextView(Context context) {
//        this(context, null);
//    }
//
//    // Default constructor when inflating from XML file
//    public AutoResizeTextView(Context context, AttributeSet attrs) {
//        this(context, attrs, 0);
//    }
//
//    // Default constructor override
//    public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) {
//        super(context, attrs, defStyle);
//        mTextSize = getTextSize();
//    }
//
//    /**
//     * When text changes, set the force resize flag to true and reset the text size.
//     */
//    @Override
//    protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) {
//        mNeedsResize = true;
//        // Since this view may be reused, it is good to reset the text size
//        resetTextSize();
//    }
//
//    /**
//     * If the text view size changed, set the force resize flag to true
//     */
//    @Override
//    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
//        if (w != oldw || h != oldh) {
//            mNeedsResize = true;
//        }
//    }
//
//    /**
//     * Register listener to receive resize notifications
//     * @param listener
//     */
//    public void setOnResizeListener(OnTextResizeListener listener) {
//        mTextResizeListener = listener;
//    }
//
//    /**
//     * Override the set text size to update our internal reference values
//     */
//    @Override
//    public void setTextSize(float size) {
//        super.setTextSize(size);
//        mTextSize = getTextSize();
//    }
//
//    /**
//     * Override the set text size to update our internal reference values
//     */
//    @Override
//    public void setTextSize(int unit, float size) {
//        super.setTextSize(unit, size);
//        mTextSize = getTextSize();
//    }
//
//    /**
//     * Override the set line spacing to update our internal reference values
//     */
//    @Override
//    public void setLineSpacing(float add, float mult) {
//        super.setLineSpacing(add, mult);
//        mSpacingMult = mult;
//        mSpacingAdd = add;
//    }
//
//    /**
//     * Set the upper text size limit and invalidate the view
//     * @param maxTextSize
//     */
//    public void setMaxTextSize(float maxTextSize) {
//        mMaxTextSize = maxTextSize;
//        requestLayout();
//        invalidate();
//    }
//
//    /**
//     * Return upper text size limit
//     * @return
//     */
//    public float getMaxTextSize() {
//        return mMaxTextSize;
//    }
//
//    /**
//     * Set the lower text size limit and invalidate the view
//     * @param minTextSize
//     */
//    public void setMinTextSize(float minTextSize) {
//        mMinTextSize = minTextSize;
//        requestLayout();
//        invalidate();
//    }
//
//    /**
//     * Return lower text size limit
//     * @return
//     */
//    public float getMinTextSize() {
//        return mMinTextSize;
//    }
//
//    /**
//     * Set flag to add ellipsis to text that overflows at the smallest text size
//     * @param addEllipsis
//     */
//    public void setAddEllipsis(boolean addEllipsis) {
//        mAddEllipsis = addEllipsis;
//    }
//
//    /**
//     * Return flag to add ellipsis to text that overflows at the smallest text size
//     * @return
//     */
//    public boolean getAddEllipsis() {
//        return mAddEllipsis;
//    }
//
//    /**
//     * Reset the text to the original size
//     */
//    public void resetTextSize() {
//        if(mTextSize > 0) {
//            super.setTextSize(TypedValue.COMPLEX_UNIT_SP, mTextSize);
//            mMaxTextSize = mTextSize;
//        }
//    }
//
//    /**
//     * Resize text after measuring
//     */
//    @Override
//    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
//        if(changed || mNeedsResize) {
//            int widthLimit = (right - left) - getCompoundPaddingLeft() - getCompoundPaddingRight();
//            int heightLimit = (bottom - top) - getCompoundPaddingBottom() - getCompoundPaddingTop();
//            resizeText(widthLimit, heightLimit);
//        }
//        super.onLayout(changed, left, top, right, bottom);
//    }
//
//
//    /**
//     * Resize the text size with default width and height
//     */
//    public void resizeText() {
//        int heightLimit = getHeight() - getPaddingBottom() - getPaddingTop();
//        int widthLimit = getWidth() - getPaddingLeft() - getPaddingRight();
//        resizeText(widthLimit, heightLimit);
//    }
//
//    /**
//     * Resize the text size with specified width and height
//     * @param width
//     * @param height
//     */
//    public void resizeText(int width, int height) {
//        CharSequence text = getText();
//        // Do not resize if the view does not have dimensions or there is no text
//        if(text == null || text.length() == 0 || height <= 0 || width <= 0 || mTextSize == 0) {
//            return;
//        }
//
//        // Get the text view's paint object
//        TextPaint textPaint = getPaint();
//
//        // Store the current text size
//        float oldTextSize = textPaint.getTextSize();
//        // If there is a max text size set, use the lesser of that and the default text size
//        float targetTextSize = mMaxTextSize > 0 ? Math.min(mTextSize, mMaxTextSize) : mTextSize;
//
//        // Get the required text height
//        int textHeight = getTextHeight(text, textPaint, width, targetTextSize);
//
//        // Until we either fit within our text view or we had reached our min text size, incrementally try smaller sizes
//        while(textHeight > height && targetTextSize > mMinTextSize) {
//            targetTextSize = Math.max(targetTextSize - 2, mMinTextSize);
//            textHeight = getTextHeight(text, textPaint, width, targetTextSize);
//        }
//
//        // If we had reached our minimum text size and still don't fit, append an ellipsis
//        if(mAddEllipsis && targetTextSize == mMinTextSize && textHeight > height) {
//            // Draw using a static layout
//            StaticLayout layout = new StaticLayout(text, textPaint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, false);
//            // Check that we have a least one line of rendered text
//            if(layout.getLineCount() > 0) {
//                // Since the line at the specific vertical position would be cut off,
//                // we must trim up to the previous line
//                int lastLine = layout.getLineForVertical(height) - 1;
//                // If the text would not even fit on a single line, clear it
//                if(lastLine < 0) {
//                    setText("");
//                }
//                // Otherwise, trim to the previous line and add an ellipsis
//                else {
//                    int start = layout.getLineStart(lastLine);
//                    int end = layout.getLineEnd(lastLine);
//                    float lineWidth = layout.getLineWidth(lastLine);
//                    float ellipseWidth = textPaint.measureText(mEllipsis);
//
//                    // Trim characters off until we have enough room to draw the ellipsis
//                    while(width < lineWidth + ellipseWidth) {
//                        lineWidth = textPaint.measureText(text.subSequence(start, --end + 1).toString());
//                    }
//                    setText(text.subSequence(0, end) + mEllipsis);
//                }
//            }
//        }
//
//        // Some devices try to auto adjust line spacing, so force default line spacing
//        // and invalidate the layout as a side effect
//        textPaint.setTextSize(targetTextSize);
//        setLineSpacing(mSpacingAdd, mSpacingMult);
//
//        // Notify the listener if registered
//        if(mTextResizeListener != null) {
//            mTextResizeListener.onTextResize(this, oldTextSize, targetTextSize);
//        }
//
//        // Reset force resize flag
//        mNeedsResize = false;
//    }
//
//    // Set the text size of the text paint object and use a static layout to render text off screen before measuring
//    private int getTextHeight(CharSequence source, TextPaint paint, int width, float textSize) {
//        // Update the text paint object
//        paint.setTextSize(textSize);
//        // Measure using a static layout
//        StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
//        return layout.getHeight();
//    }
//
//}