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
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。
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);
}
}
我的方法是:
public void changeTextSize(int initialSize, TextView tv) {
DisplayMetrics displayMetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
double width = displayMetrics.widthPixels / displayMetrics.xdpi;
double height = displayMetrics.heightPixels / displayMetrics.ydpi;
Log.i("LOG", "The width of the tested emulator is: " + width);
Log.i("LOG", "The height of the tested emulator is: " + height);
double scale = Math.min(width / 2.25, height / 4.0); //See the logcat >>> width = 2.25 and heigt = 4.0
tv.setTextSize(TypedValue.COMPLEX_UNIT_SP, (int) (initialSize * scale));
}
例如:
changeTextSize(16, findViewById(R.id.myTextView));
changeTextSize(12, findViewById(R.id.myEditText));
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;
}
}
以下是我采取的方法。这很简单。它使用连续逼近来集中于字体大小，通常可以在不到10次迭代中计算出来。只需将“activityWidth”替换为你用来显示文本的视图的宽度。在我的示例中，它被设置为与屏幕宽度相同的私有字段。初始fontsize 198只在该方法产生异常的情况下设置(这真的不应该发生):
private float GetFontSizeForScreenWidth(String text)
{
float fontsize = 198;
try
{
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.RED);
Typeface typeface = Typeface.create("Helvetica", Typeface.BOLD);
paint.setTypeface(typeface);
paint.setTextAlign(Align.CENTER);
int lowVal = 0;
int highVal = 2000;
int currentVal = highVal;
/*
* Successively approximate the screen size until it is
* within 2 pixels of the maximum screen width. Generally
* this will get you to the closest font size within about 10
* iterations.
*/
do
{
paint.setTextSize(currentVal);
float textWidth = paint.measureText(text);
float diff = activityWidth - textWidth;
if ((diff >= 0) && (diff <= 2))
{
fontsize = paint.getTextSize();
return fontsize;
}
if (textWidth > activityWidth)
highVal = currentVal;
else if (textWidth < activityWidth)
lowVal = currentVal;
else
{
fontsize = paint.getTextSize();
return fontsize;
}
currentVal = (highVal - lowVal) / 2 + lowVal;
} while (true);
}
catch (Exception ex)
{
return fontsize;
}
}
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。
