我正在寻找一种最佳的方法来调整包装文本在一个TextView，使它将适合它的getHeight和getWidth界限。我不是简单地寻找一种方法来包装文本-我想确保它既包装，又足够小，完全适合在屏幕上。
我在StackOverflow上看到了一些需要自动调整大小的情况，但它们要么是非常特殊的情况下的hack解决方案，没有解决方案，或涉及重新绘制TextView递归直到它足够小(这是内存紧张，迫使用户观看文本收缩一步一步与每次递归)。
但我相信有人已经找到了一个很好的解决方案，它不涉及我正在做的事情:编写几个繁重的例程来解析和测量文本，调整文本的大小，然后重复，直到找到一个合适的小尺寸。
TextView使用什么例程来包装文本?难道这些不能用来预测文本是否足够小吗?
是否有一个最佳实践的方法来自动调整TextView的大小，以适应，包装，在它的getHeight和getWidth边界?
当前回答
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;
}
}
}
其他回答
因为我一直在寻找这个，而我刚刚找到了一个解决方案，但这里没有，我将把它写在这里，以供将来参考。
注意:这段代码是直接从谷歌Android棒棒糖拨号器一段时间后，我不记得如果改变在当时。此外，我不知道这是在哪个许可证下，但我有理由认为它是Apache 2.0。
类ResizeTextView，实际的视图
public class ResizeTextView extends TextView {
private final int mOriginalTextSize;
private final int mMinTextSize;
private final static int sMinSize = 20;
public ResizeTextView(Context context, AttributeSet attrs) {
super(context, attrs);
mOriginalTextSize = (int) getTextSize();
mMinTextSize = (int) sMinSize;
}
@Override
protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
super.onTextChanged(text, start, lengthBefore, lengthAfter);
ViewUtil.resizeText(this, mOriginalTextSize, mMinTextSize);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
ViewUtil.resizeText(this, mOriginalTextSize, mMinTextSize);
}
这个ResizeTextView类可以扩展TextView和它所有的孩子，我的理解，所以EditText以及。
ViewUtil类带有resizeText方法(…)
/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import android.graphics.Paint;
import android.util.TypedValue;
import android.widget.TextView;
public class ViewUtil {
private ViewUtil() {}
public static void resizeText(TextView textView, int originalTextSize, int minTextSize) {
final Paint paint = textView.getPaint();
final int width = textView.getWidth();
if (width == 0) return;
textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, originalTextSize);
float ratio = width / paint.measureText(textView.getText().toString());
if (ratio <= 1.0f) {
textView.setTextSize(TypedValue.COMPLEX_UNIT_PX,
Math.max(minTextSize, originalTextSize * ratio));
}
}
}
您应该将您的视图设置为
<yourpackage.yourapp.ResizeTextView
android:layout_width="match_parent"
android:layout_height="64dp"
android:gravity="center"
android:maxLines="1"/>
希望能有所帮助!
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;
}
}
Android 4.x的一个变通方案:
我找到了AutoResizeTextView，它在我的Android 2.1模拟器上工作得很好。我非常喜欢它。但不幸的是，它在我自己的4.0.4手机和4.1模拟器上失败了。经过尝试，我发现它可以通过在xml中的AutoResizeTextView类中添加以下属性轻松解决:
android：ellipsize=“none” android：singleLine=“true”
有了上面的两行，现在AutoResizeTextView在我的2.1和4.1模拟器和我自己的4.0.4手机上完美地工作。
希望这对你有所帮助。: -)
从2018年6月起，Android正式开始支持Android 4.0 (API级别14)及更高版本的此功能。 查看它在:Autosizing TextViews
Android 8.0 (API级别26)及更高版本:
<?xml version="1.0" encoding="utf-8"?>
<TextView
android:layout_width="match_parent"
android:layout_height="200dp"
android:autoSizeTextType="uniform"
android:autoSizeMinTextSize="12sp"
android:autoSizeMaxTextSize="100sp"
android:autoSizeStepGranularity="2sp" />
编程:
setAutoSizeTextTypeUniformWithConfiguration(int autoSizeMinTextSize, int autoSizeMaxTextSize,
int autoSizeStepGranularity, int unit)
textView.setAutoSizeTextTypeUniformWithConfiguration(
1, 17, 1, TypedValue.COMPLEX_UNIT_DIP);
Android 8.0之前的Android版本(API级别26):
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="match_parent"
android:layout_height="200dp"
app:autoSizeTextType="uniform"
app:autoSizeMinTextSize="12sp"
app:autoSizeMaxTextSize="100sp"
app:autoSizeStepGranularity="2sp" />
</LinearLayout>
编程:
TextViewCompat.setAutoSizeTextTypeUniformWithConfiguration(
TextView textView, int autoSizeMinTextSize, int autoSizeMaxTextSize, int autoSizeStepGranularity, int unit)
TextViewCompat.setAutoSizeTextTypeUniformWithConfiguration(textView, 1, 17, 1,
TypedValue.COMPLEX_UNIT_DIP);
注意:TextView必须有layout_width="match_parent"或绝对大小!
在2017年谷歌IO大会上，谷歌介绍了TextView的autoSize属性
https://youtu.be/fjUdJ2aVqE4
<android.support.v7.widget.AppCompatTextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="@string/my_text"
app:autoSizeTextType="uniform"
app:autoSizeMaxTextSize="10sp"
app:autoSizeMinTextSize="6sp"
app:autoSizeStepGranularity="1sp"/>
