我只是借用了一些其他人的想法，并在下面写了一些代码，可能会有帮助。

import android.content.Context;
import android.graphics.Canvas;
import android.text.Layout.Alignment;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.widget.TextView;

public class AutoResizeTextView extends TextView {
    private static final int MAX_SIZE = 1000;

    private static final int MIN_SIZE = 5;

    private TextPaint mTextPaint;

    private float mSpacingMult = 1.0f;

    private float mSpacingAdd = 0.0f;

    private boolean needAdapt = false;

    private boolean adapting = false;

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

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

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

    private void init() {
        mTextPaint = new TextPaint();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (adapting) {
            return;
        }
        if (needAdapt) {
            adaptTextSize();
        } else {
            super.onDraw(canvas);
        }
    }

    private void adaptTextSize() {
        CharSequence text = getText();
        int viewWidth = getMeasuredWidth();
        int viewHeight = getMeasuredHeight();

        if (viewWidth==0 || viewHeight==0
                || TextUtils.isEmpty(text)) {
            return;
        }

        adapting = true;
        /* binary search */
        int bottom=MIN_SIZE, top=MAX_SIZE, mid = 0;
        while (bottom <= top) {
            mid = (bottom + top)/2;
            mTextPaint.setTextSize(mid);
            int textWidth = (int) mTextPaint.measureText(text, 0, text.length());
            int textHeight = getTextHeight(text, viewWidth);
            if (textWidth<viewWidth && textHeight<viewHeight) {
                bottom = mid+1;
            } else {
                top = mid-1;
            }
        }

        int newSize = mid-1;
        setTextSize(TypedValue.COMPLEX_UNIT_PX, newSize);

        adapting=false;
        needAdapt = false;

        invalidate();
    }

    private int getTextHeight(CharSequence text, int targetWidth) {
        StaticLayout layout = new StaticLayout(text, mTextPaint, targetWidth,
                Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
        return layout.getHeight();
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        needAdapt = true;
    }

    @Override
    protected void onTextChanged(CharSequence text, int start,
            int lengthBefore, int lengthAfter) {
        super.onTextChanged(text, start, lengthBefore, lengthAfter);
        needAdapt = true;
    }

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

我为此写了一篇博客。

我根据Kirill Grouchnikov关于在新的android market应用中使用的自定义组件的博客文章创建了一个名为ResizableButton的组件。我把src代码放在这里。

另一方面，mosabua读了我的文章，并告诉我他将开源他的实现，这比我的更快。我希望他能尽快发布:)

这是一个简单的解决方案，使用TextView本身和textchangedlistens添加到它:

expressionView = (TextView) findViewById(R.id.expressionView);
expressionView.addTextChangedListener(textAutoResizeWatcher(expressionView, 25, 55));

private TextWatcher textAutoResizeWatcher(final TextView view, final int MIN_SP, final int MAX_SP) {
    return new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {}

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {}

        @Override
        public void afterTextChanged(Editable editable) {

            final int widthLimitPixels = view.getWidth() - view.getPaddingRight() - view.getPaddingLeft();
            Paint paint = new Paint();
            float fontSizeSP = pixelsToSp(view.getTextSize());
            paint.setTextSize(spToPixels(fontSizeSP));

            String viewText = view.getText().toString();

            float widthPixels = paint.measureText(viewText);

            // Increase font size if necessary.
            if (widthPixels < widthLimitPixels){
                while (widthPixels < widthLimitPixels && fontSizeSP <= MAX_SP){
                    ++fontSizeSP;
                    paint.setTextSize(spToPixels(fontSizeSP));
                    widthPixels = paint.measureText(viewText);
                }
                --fontSizeSP;
            }
            // Decrease font size if necessary.
            else {
                while (widthPixels > widthLimitPixels || fontSizeSP > MAX_SP) {
                    if (fontSizeSP < MIN_SP) {
                        fontSizeSP = MIN_SP;
                        break;
                    }
                    --fontSizeSP;
                    paint.setTextSize(spToPixels(fontSizeSP));
                    widthPixels = paint.measureText(viewText);
                }
            }

            view.setTextSize(fontSizeSP);
        }
    };
}

private float pixelsToSp(float px) {
    float scaledDensity = getResources().getDisplayMetrics().scaledDensity;
    return px/scaledDensity;
}

private float spToPixels(float sp) {
    float scaledDensity = getResources().getDisplayMetrics().scaledDensity;
    return sp * scaledDensity;
}

这种方法将根据需要增加或减少字体大小以适应文本，尊重作为参数接收的MIN_SP和MAX_SP边界。

作为一名手机开发者，我很遗憾地发现没有任何原生的支持自动调整大小的功能。我的搜索没有找到任何对我有用的东西，最后，我花了大半个周末的时间创建了我自己的自动调整文本视图。我将在这里发布代码，希望它对其他人有用。

这个类使用带有原始文本视图的文本绘制的静态布局来测量高度。从那里，我后退2个字体像素，重新测量，直到我有一个合适的大小。在最后，如果文本仍然不合适，我附加一个省略号。我需要动画文本和重用视图，这似乎在我拥有的设备上工作得很好，似乎运行得足够快。

/**
 *               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 = 20;

    // 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 = 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 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_PX, 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;
        }

        if (getTransformationMethod() != null) {
            text = getTransformationMethod().getTransformation(text, this);
        }

        // 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
            // modified: use a copy of TextPaint for measuring
            TextPaint paint = new TextPaint(textPaint);
            // Draw using a static layout
            StaticLayout layout = new StaticLayout(text, paint, 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
        setTextSize(TypedValue.COMPLEX_UNIT_PX, 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) {
        // modified: make a copy of the original TextPaint object for measuring
        // (apparently the object gets modified while measuring, see also the
        // docs for TextView.getPaint() (which states to access it read-only)
        TextPaint paintCopy = new TextPaint(paint);
        // Update the text paint object
        paintCopy.setTextSize(textSize);
        // Measure using a static layout
        StaticLayout layout = new StaticLayout(source, paintCopy, width, Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
        return layout.getHeight();
    }

}

警告。有一个影响Android 3.1 - 4.04的重要修复错误，导致所有AutoResizingTextView小部件无法工作。请阅读:https://stackoverflow.com/a/21851157/2075875

我只是借用了一些其他人的想法，并在下面写了一些代码，可能会有帮助。

import android.content.Context;
import android.graphics.Canvas;
import android.text.Layout.Alignment;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.widget.TextView;

public class AutoResizeTextView extends TextView {
    private static final int MAX_SIZE = 1000;

    private static final int MIN_SIZE = 5;

    private TextPaint mTextPaint;

    private float mSpacingMult = 1.0f;

    private float mSpacingAdd = 0.0f;

    private boolean needAdapt = false;

    private boolean adapting = false;

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

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

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

    private void init() {
        mTextPaint = new TextPaint();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (adapting) {
            return;
        }
        if (needAdapt) {
            adaptTextSize();
        } else {
            super.onDraw(canvas);
        }
    }

    private void adaptTextSize() {
        CharSequence text = getText();
        int viewWidth = getMeasuredWidth();
        int viewHeight = getMeasuredHeight();

        if (viewWidth==0 || viewHeight==0
                || TextUtils.isEmpty(text)) {
            return;
        }

        adapting = true;
        /* binary search */
        int bottom=MIN_SIZE, top=MAX_SIZE, mid = 0;
        while (bottom <= top) {
            mid = (bottom + top)/2;
            mTextPaint.setTextSize(mid);
            int textWidth = (int) mTextPaint.measureText(text, 0, text.length());
            int textHeight = getTextHeight(text, viewWidth);
            if (textWidth<viewWidth && textHeight<viewHeight) {
                bottom = mid+1;
            } else {
                top = mid-1;
            }
        }

        int newSize = mid-1;
        setTextSize(TypedValue.COMPLEX_UNIT_PX, newSize);

        adapting=false;
        needAdapt = false;

        invalidate();
    }

    private int getTextHeight(CharSequence text, int targetWidth) {
        StaticLayout layout = new StaticLayout(text, mTextPaint, targetWidth,
                Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
        return layout.getHeight();
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        needAdapt = true;
    }

    @Override
    protected void onTextChanged(CharSequence text, int start,
            int lengthBefore, int lengthAfter) {
        super.onTextChanged(text, start, lengthBefore, lengthAfter);
        needAdapt = true;
    }

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

我刚刚创建了以下方法(基于Chase的想法)，如果你想在任何画布上绘制文本，它可能会帮助你:

private static void drawText(Canvas canvas, int xStart, int yStart,
        int xWidth, int yHeigth, String textToDisplay,
        TextPaint paintToUse, float startTextSizeInPixels,
        float stepSizeForTextSizeSteps) {

    // Text view line spacing multiplier
    float mSpacingMult = 1.0f;
    // Text view additional line spacing
    float mSpacingAdd = 0.0f;
    StaticLayout l = null;
    do {
        paintToUse.setTextSize(startTextSizeInPixels);
        startTextSizeInPixels -= stepSizeForTextSizeSteps;
        l = new StaticLayout(textToDisplay, paintToUse, xWidth,
                Alignment.ALIGN_NORMAL, mSpacingMult, mSpacingAdd, true);
    } while (l.getHeight() > yHeigth);

    int textCenterX = xStart + (xWidth / 2);
    int textCenterY = (yHeigth - l.getHeight()) / 2;

    canvas.save();
    canvas.translate(textCenterX, textCenterY);
    l.draw(canvas);
    canvas.restore();
}

这可以在任何自定义视图的任何onDraw()方法中使用。