Android Open Source - SizeAdjustingTextView Size Adjusting Text View

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License

The source code is released under:

GNU General Public License

Java Source Code

package com.elliott.chenger.sizeadjustingtextview.view;
/* ww w.java  2s  .c om*/
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;

/**
 * 
 * SizeAdjustingTextView is a TextView that adjusts text size
 *  depending if or if not it will fit in the view bounds.
 * Copyright (C) 2014 Elliott Chenger
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 * 
 * @author Elliott Chenger
 * @since Jan 18, 2014
 * @author Chase Colburn
 * @since Apr 4, 2011
 * 
 */
public class SizeAdjustingTextView extends TextView{

  // Minimum text size for this text view
  public static final float MIN_TEXT_SIZE = 20;

  // Our ellipse string
  private static final String mEllipsis = "...";

  // 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 = 0;

  // 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 SizeAdjustingTextView(Context context) {
    this(context, null);
  }

  // Default constructor when inflating from XML file
  public SizeAdjustingTextView(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
  }

  // Default constructor override
  public SizeAdjustingTextView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    mTextSize = getTextSize();
  }

  @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();
  }

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

  @Override
  protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    if (w != oldw || h != oldh) {
      mNeedsResize = true;
    }
  }


  @Override
  public void setTextSize(float size) {
    super.setTextSize(size);
    mTextSize = getTextSize();
  }

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

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

  public void setMaxTextSize(float maxTextSize) {
    mMaxTextSize = maxTextSize;
    requestLayout();
    invalidate();
  }

  public float getMaxTextSize() {
    return mMaxTextSize;
  }

  public void setMinTextSize(float minTextSize) {
    mMinTextSize = minTextSize;
    requestLayout();
    invalidate();
  }

  public float getMinTextSize() {
    return mMinTextSize;
  }

  public void setAddEllipsis(boolean addEllipsis) {
    mAddEllipsis = addEllipsis;
  }

  public boolean getAddEllipsis() {
    return mAddEllipsis;
  }

  public void resetTextSize() {
    if(mTextSize > 0) {
      super.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize);
      mMaxTextSize = mTextSize;
    }
  }

  @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);
  }


  public void resizeText() {
    int heightLimit = getHeight() - getPaddingBottom() - getPaddingTop();
    int widthLimit = getWidth() - getPaddingLeft() - getPaddingRight();
    resizeText(widthLimit, heightLimit);
  }

  public void resizeText(int width, int height) {
    CharSequence text = getText();
    if(text == null || text.length() == 0 || height <= 0 || width <= 0 || mTextSize == 0) {
      return;
    }
    float newTextSize = findNewTextSize(width, height, text);
    changeTextSize(newTextSize);
    mNeedsResize = false;
  }

  private void changeTextSize(float newTextSize) {
    setTextSize(TypedValue.COMPLEX_UNIT_PX,newTextSize);
    setLineSpacing(mSpacingAdd, mSpacingMult);
  }

  private float findNewTextSize(int width, int height, CharSequence text) {
    TextPaint textPaint = new TextPaint(getPaint());

    float targetTextSize = textPaint.getTextSize();

    int textHeight = getTextHeight(text, textPaint, width, targetTextSize);
    while(textHeight > height && targetTextSize > mMinTextSize) {
      targetTextSize = Math.max(targetTextSize - 1, mMinTextSize);
      textHeight = getTextHeight(text, textPaint, width, targetTextSize);
    }
    return targetTextSize;
  }

  private int getTextHeight(CharSequence source, TextPaint paint, int width, float textSize) {
    paint.setTextSize(textSize);
    StaticLayout layout = new StaticLayout(source, paint, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
    return layout.getHeight();
  }

}

Java Source Code List

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