我希望这对你有所帮助

import android.content.Context;
import android.graphics.Rect;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.widget.TextView;

/* Based on 
 * from http://stackoverflow.com/questions/2617266/how-to-adjust-text-font-size-to-fit-textview
 */
public class FontFitTextView extends TextView {

private static float MAX_TEXT_SIZE = 20;

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

public FontFitTextView(Context context, AttributeSet attrs) {
    super(context, attrs);

    float size = this.getTextSize();
    if (size > MAX_TEXT_SIZE)
        setTextSize(MAX_TEXT_SIZE);
}

private void refitText(String text, int textWidth) {
    if (textWidth > 0) {
        float availableWidth = textWidth - this.getPaddingLeft()
                - this.getPaddingRight();

        TextPaint tp = getPaint();
        Rect rect = new Rect();
        tp.getTextBounds(text, 0, text.length(), rect);
        float size = rect.width();

        if (size > availableWidth)
            setTextScaleX(availableWidth / size);
    }
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    int parentWidth = MeasureSpec.getSize(widthMeasureSpec);
    int parentHeight = MeasureSpec.getSize(heightMeasureSpec);
    refitText(this.getText().toString(), parentWidth);
    this.setMeasuredDimension(parentWidth, parentHeight);
}

@Override
protected void onTextChanged(final CharSequence text, final int start,
        final int before, final int after) {
    refitText(text.toString(), this.getWidth());
}

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    if (w != oldw) {
        refitText(this.getText().toString(), w);
    }
}
}

注意:我使用MAX_TEXT_SIZE在文本大小大于20的情况下，因为我不想让大字体适用于我的视图，如果这不是你的情况下，你可以简单地删除它。

如果有人需要它，这里是相同的代码片段，但Xamarin.Android。

/**
 *               DO WHAT YOU WANT TO PUBLIC LICENSE
 *                    Version 1, December 2017
 * 
 * Copyright (C) 2017 Nathan Westfall
 * 
 * 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.
 */

using Android.Content;
using Android.Runtime;
using Android.Widget;
using Android.Util;
using Android.Text;

using Java.Lang;

namespace My.Text
{
    public class AutoResizeTextView : TextView
    {
        public const float MIN_TEXT_SIZE = 20;

        public interface OnTextResizeListener
        {
            void OnTextResize(TextView textView, float oldSize, float newSize);
        }

        private const string mEllipsis = "...";

        private OnTextResizeListener mTextResizeListener;

        private bool mNeedsResize = false;

        private float mTextSize;

        private float mMaxTextSize = 0;

        private float mMinTextSize = MIN_TEXT_SIZE;

        private float mSpacingMult = 1.0f;

        private float mSpacingAdd = 0.0f;

        public bool AddEllipsis { get; set; } = true;

        public AutoResizeTextView(Context context) : this(context, null) { }

        public AutoResizeTextView(Context context, IAttributeSet attrs) : this(context, attrs, 0) { }

        public AutoResizeTextView(Context context, IAttributeSet attrs, int defStyle): base(context, attrs, defStyle)
        {
            mTextSize = TextSize;
        }

        protected override void OnTextChanged(ICharSequence text, int start, int lengthBefore, int lengthAfter)
        {
            base.OnTextChanged(text, start, lengthBefore, lengthAfter);

            mNeedsResize = true;

            ResetTextSize();
        }

        protected override void OnSizeChanged(int w, int h, int oldw, int oldh)
        {
            base.OnSizeChanged(w, h, oldw, oldh);

            if (w != oldw || h != oldh)
                mNeedsResize = true;
        }

        public void SetOnResizeListener(OnTextResizeListener listener)
        {
            mTextResizeListener = listener;
        }

        public override void SetTextSize([GeneratedEnum] ComplexUnitType unit, float size)
        {
            base.SetTextSize(unit, size);

            mTextSize = TextSize;
        }

        public override void SetLineSpacing(float add, float mult)
        {
            base.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 ResetTextSize()
        {
            if(mTextSize > 0)
            {
                base.SetTextSize(ComplexUnitType.Px, mTextSize);
                mMaxTextSize = mTextSize;
            }
        }

        protected override void OnLayout(bool changed, int left, int top, int right, int bottom)
        {
            if(changed || mNeedsResize)
            {
                int widthLimit = (right - left) - CompoundPaddingLeft - CompoundPaddingRight;
                int heightLimit = (bottom - top) - CompoundPaddingBottom - CompoundPaddingTop;
                ResizeText(widthLimit, heightLimit);
            }
            base.OnLayout(changed, left, top, right, bottom);

            base.OnLayout(changed, left, top, right, bottom);
        }

        public void ResizeText()
        {
            int heightLimit = Height - PaddingBottom - PaddingTop;
            int widthLimit = Width - PaddingLeft - PaddingRight;
            ResizeText(widthLimit, heightLimit);
        }

        public void ResizeText(int width, int height)
        {
            var text = TextFormatted;
            if (text == null || text.Length() == 0 || height <= 0 || width <= 0 || mTextSize == 0)
                return;

            if (TransformationMethod != null)
                text = TransformationMethod.GetTransformationFormatted(TextFormatted, this);

            TextPaint textPaint = Paint;

            float oldTextSize = textPaint.TextSize;
            float targetTextSize = mMaxTextSize > 0 ? System.Math.Min(mTextSize, mMaxTextSize) : mTextSize;

            int textHeight = GetTextHeight(text, textPaint, width, targetTextSize);

            while(textHeight > height && targetTextSize > mMinTextSize)
            {
                targetTextSize = System.Math.Max(targetTextSize - 2, mMinTextSize);
                textHeight = GetTextHeight(text, textPaint, width, targetTextSize);
            }

            if(AddEllipsis && targetTextSize == mMinTextSize && textHeight > height)
            {
                TextPaint paint = new TextPaint(textPaint);

                StaticLayout layout = new StaticLayout(text, paint, width, Layout.Alignment.AlignNormal, mSpacingMult, mSpacingAdd, false);
                if(layout.LineCount > 0)
                {
                    int lastLine = layout.GetLineForVertical(height) - 1;
                    if (lastLine < 0)
                        SetText("", BufferType.Normal);
                    else
                    {
                        int start = layout.GetLineStart(lastLine);
                        int end = layout.GetLineEnd(lastLine);
                        float lineWidth = layout.GetLineWidth(lastLine);
                        float ellipseWidth = textPaint.MeasureText(mEllipsis);

                        while (width < lineWidth + ellipseWidth)
                            lineWidth = textPaint.MeasureText(text.SubSequence(start, --end + 1).ToString());
                        SetText(text.SubSequence(0, end) + mEllipsis, BufferType.Normal);
                    }
                }
            }

            SetTextSize(ComplexUnitType.Px, targetTextSize);
            SetLineSpacing(mSpacingAdd, mSpacingMult);

            mTextResizeListener?.OnTextResize(this, oldTextSize, targetTextSize);

            mNeedsResize = false;
        }

        private int GetTextHeight(ICharSequence source, TextPaint paint, int width, float textSize)
        {
            TextPaint paintCopy = new TextPaint(paint);
            paintCopy.TextSize = textSize;
            StaticLayout layout = new StaticLayout(source, paintCopy, width, Layout.Alignment.AlignNormal, mSpacingMult, mSpacingAdd, false);
            return layout.Height;
        }
    }
}

这里还有另一个解决方案，只是为了好玩。它可能不是很有效，但它确实处理了文本的高度和宽度，以及有标记的文本。

@Override
protected void onMeasure(final int widthMeasureSpec, final int heightMeasureSpec)
{
    if ((MeasureSpec.getMode(widthMeasureSpec) != MeasureSpec.UNSPECIFIED)
            && (MeasureSpec.getMode(heightMeasureSpec) != MeasureSpec.UNSPECIFIED)) {

        final float desiredWidth = MeasureSpec.getSize(widthMeasureSpec);
        final float desiredHeight = MeasureSpec.getSize(heightMeasureSpec);

        float textSize = getTextSize();
        float lastScale = Float.NEGATIVE_INFINITY;
        while (textSize > MINIMUM_AUTO_TEXT_SIZE_PX) {
            // Measure how big the textview would like to be with the current text size.
            super.onMeasure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);

            // Calculate how much we'd need to scale it to fit the desired size, and
            // apply that scaling to the text size as an estimate of what we need.
            final float widthScale = desiredWidth / getMeasuredWidth();
            final float heightScale = desiredHeight / getMeasuredHeight();
            final float scale = Math.min(widthScale, heightScale);

            // If we don't need to shrink the text, or we don't seem to be converging, we're done.
            if ((scale >= 1f) || (scale <= lastScale)) {
                break;
            }

            // Shrink the text size and keep trying.
            textSize = Math.max((float) Math.floor(scale * textSize), MINIMUM_AUTO_TEXT_SIZE_PX);
            setTextSize(TypedValue.COMPLEX_UNIT_PX, textSize);
            lastScale = scale;
        }
    }
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

问题是关于如何在Button上有这个功能;对于TextView来说，它很容易，并且通过遵循这里的官方文档可以很好地工作。

Style.xml:

    <style name="Widget.Button.CustomStyle" parent="Widget.MaterialComponents.Button">
        <item name="android:minHeight">50dp</item>
        <item name="android:maxWidth">300dp</item>
        <item name="android:textStyle">bold</item>
        <item name="android:textSize">16sp</item>
        <item name="backgroundTint">@color/white</item>
        <item name="cornerRadius">25dp</item>
        <item name="autoSizeTextType">uniform</item>
        <item name="autoSizeMinTextSize">10sp</item>
        <item name="autoSizeMaxTextSize">16sp</item>
        <item name="autoSizeStepGranularity">2sp</item>
        <item name="android:maxLines">1</item>
        <item name="android:textColor">@color/colorPrimary</item>
        <item name="android:insetTop">0dp</item>
        <item name="android:insetBottom">0dp</item>
        <item name="android:lineSpacingExtra">4sp</item>
        <item name="android:gravity">center</item>
    </style>

用法:

<com.google.android.material.button.MaterialButton
            android:id="@+id/blah"
            style="@style/Widget.Button.CustomStyle"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginStart="16dp"
            android:layout_marginEnd="16dp"
            android:text="Your long text, to the infinity and beyond!!! Why not :)" />

结果:

参考ScalableTextView.java这里自动适合Android的TextView。我已经添加了代码来根据文本长度收缩和扩展TextView

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:)