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
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"/>
其他回答
这个解决方案适合我们:
public class CustomFontButtonTextFit extends CustomFontButton
{
private final float DECREMENT_FACTOR = .1f;
public CustomFontButtonTextFit(Context context) {
super(context);
}
public CustomFontButtonTextFit(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CustomFontButtonTextFit(Context context, AttributeSet attrs,
int defStyle) {
super(context, attrs, defStyle);
}
private synchronized 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();
while(size > availableWidth)
{
setTextSize( getTextSize() - DECREMENT_FACTOR );
tp = getPaint();
tp.getTextBounds(text, 0, text.length(), rect);
size = rect.width();
}
}
}
@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);
if(parentWidth < getSuggestedMinimumWidth())
parentWidth = getSuggestedMinimumWidth();
if(parentHeight < getSuggestedMinimumHeight())
parentHeight = getSuggestedMinimumHeight();
this.setMeasuredDimension(parentWidth, parentHeight);
}
@Override
protected void onTextChanged(final CharSequence text, final int start,
final int before, final int after)
{
super.onTextChanged(text, start, before, after);
refitText(text.toString(), this.getWidth());
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh)
{
super.onSizeChanged(w, h, oldw, oldh);
if (w != oldw)
refitText(this.getText().toString(), w);
}
}
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;
}
}
实际上解决方案是在谷歌的DialogTitle类…虽然它不如公认的方法有效，但它更简单，也更容易适应。
public class SingleLineTextView extends TextView {
public SingleLineTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
setSingleLine();
setEllipsize(TruncateAt.END);
}
public SingleLineTextView(Context context, AttributeSet attrs) {
super(context, attrs);
setSingleLine();
setEllipsize(TruncateAt.END);
}
public SingleLineTextView(Context context) {
super(context);
setSingleLine();
setEllipsize(TruncateAt.END);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
final Layout layout = getLayout();
if (layout != null) {
final int lineCount = layout.getLineCount();
if (lineCount > 0) {
final int ellipsisCount = layout.getEllipsisCount(lineCount - 1);
if (ellipsisCount > 0) {
final float textSize = getTextSize();
// textSize is already expressed in pixels
setTextSize(TypedValue.COMPLEX_UNIT_PX, (textSize - 1));
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
}
}
}
}
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!
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。
