背景
经过大量搜索自动调整 TextView 大小的最佳解决方案(根据内容、大小、最小和最大行以及字体大小限制)，我为这一切做了一个合并的解决方案，here .
注意:我不使用其他解决方案，因为它们效果不佳，每个解决方案都有自己的问题(某些内容不受支持，文本超出 TextView，文本被截断，...)。
其工作原理演示:
https://raw.githubusercontent.com/AndroidDeveloperLB/AutoFitTextView/master/animationPreview.gif
问题
在某些情况下，一行的最后一个字符会换行到下一行，如下所示:
绿色是 TextView 的边界，红色是外部。
代码
基本上，给定 TextView 的大小、其最小和最大字体大小、最小和最大行数以及应该包含的内容(文本)，它会找到(使用二分搜索)适合 TextView 边界的字体大小.
该代码已在 Github 中提供，但这里只是以防万一:
public class AutoResizeTextView extends AppCompatTextView {
private static final int NO_LINE_LIMIT = -1;
private final RectF _availableSpaceRect = new RectF();
private final SizeTester _sizeTester;
private float _maxTextSize, _spacingMult = 1.0f, _spacingAdd = 0.0f, _minTextSize;
private int _widthLimit, _maxLines;
private boolean _initialized = false;
private TextPaint _paint;
private interface SizeTester {
/**
* @param suggestedSize Size of text to be tested
* @param availableSpace available space in which text must fit
* @return an integer < 0 if after applying {@code suggestedSize} to
* text, it takes less space than {@code availableSpace}, > 0
* otherwise
*/
int onTestSize(int suggestedSize, RectF availableSpace);
}
public AutoResizeTextView(final Context context) {
this(context, null, android.R.attr.textViewStyle);
}
public AutoResizeTextView(final Context context, final AttributeSet attrs) {
this(context, attrs, android.R.attr.textViewStyle);
}
public AutoResizeTextView(final Context context, final AttributeSet attrs, final int defStyle) {
super(context, attrs, defStyle);
// using the minimal recommended font size
_minTextSize = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 12, getResources().getDisplayMetrics());
_maxTextSize = getTextSize();
_paint = new TextPaint(getPaint());
if (_maxLines == 0)
// no value was assigned during construction
_maxLines = NO_LINE_LIMIT;
// prepare size tester:
_sizeTester = new SizeTester() {
final RectF textRect = new RectF();
@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
@Override
public int onTestSize(final int suggestedSize, final RectF availableSPace) {
_paint.setTextSize(suggestedSize);
final TransformationMethod transformationMethod = getTransformationMethod();
final String text;
if (transformationMethod != null)
text = transformationMethod.getTransformation(getText(), AutoResizeTextView.this).toString();
else
text = getText().toString();
final boolean singleLine = getMaxLines() == 1;
if (singleLine) {
textRect.bottom = _paint.getFontSpacing();
textRect.right = _paint.measureText(text);
} else {
final StaticLayout layout = new StaticLayout(text, _paint, _widthLimit, Alignment.ALIGN_NORMAL, _spacingMult, _spacingAdd, true);
// return early if we have more lines
if (getMaxLines() != NO_LINE_LIMIT && layout.getLineCount() > getMaxLines())
return 1;
textRect.bottom = layout.getHeight();
int maxWidth = -1;
for (int i = 0; i < layout.getLineCount(); i++)
if (maxWidth < layout.getLineRight(i) - layout.getLineLeft(i))
maxWidth = (int) layout.getLineRight(i) - (int) layout.getLineLeft(i);
textRect.right = maxWidth;
}
textRect.offsetTo(0, 0);
if (availableSPace.contains(textRect))
// may be too small, don't worry we will find the best match
return -1;
// else, too big
return 1;
}
};
_initialized = true;
}
@Override
public void setAllCaps(boolean allCaps) {
super.setAllCaps(allCaps);
adjustTextSize();
}
@Override
public void setTypeface(final Typeface tf) {
super.setTypeface(tf);
adjustTextSize();
}
@Override
public void setTextSize(final float size) {
_maxTextSize = size;
adjustTextSize();
}
@Override
public void setMaxLines(final int maxlines) {
super.setMaxLines(maxlines);
_maxLines = maxlines;
adjustTextSize();
}
@Override
public int getMaxLines() {
return _maxLines;
}
@Override
public void setSingleLine() {
super.setSingleLine();
_maxLines = 1;
adjustTextSize();
}
@Override
public void setSingleLine(final boolean singleLine) {
super.setSingleLine(singleLine);
if (singleLine)
_maxLines = 1;
else _maxLines = NO_LINE_LIMIT;
adjustTextSize();
}
@Override
public void setLines(final int lines) {
super.setLines(lines);
_maxLines = lines;
adjustTextSize();
}
@Override
public void setTextSize(final int unit, final float size) {
final Context c = getContext();
Resources r;
if (c == null)
r = Resources.getSystem();
else r = c.getResources();
_maxTextSize = TypedValue.applyDimension(unit, size, r.getDisplayMetrics());
adjustTextSize();
}
@Override
public void setLineSpacing(final float add, final float mult) {
super.setLineSpacing(add, mult);
_spacingMult = mult;
_spacingAdd = add;
}
/**
* Set the lower text size limit and invalidate the view
*
* @param minTextSize
*/
public void setMinTextSize(final float minTextSize) {
_minTextSize = minTextSize;
adjustTextSize();
}
private void adjustTextSize() {
// This is a workaround for truncated text issue on ListView, as shown here: https://github.com/AndroidDeveloperLB/AutoFitTextView/pull/14
// TODO think of a nicer, elegant solution.
// post(new Runnable()
// {
// @Override
// public void run()
// {
if (!_initialized)
return;
final int startSize = (int) _minTextSize;
final int heightLimit = getMeasuredHeight() - getCompoundPaddingBottom() - getCompoundPaddingTop();
_widthLimit = getMeasuredWidth() - getCompoundPaddingLeft() - getCompoundPaddingRight();
if (_widthLimit <= 0)
return;
_paint = new TextPaint(getPaint());
_availableSpaceRect.right = _widthLimit;
_availableSpaceRect.bottom = heightLimit;
superSetTextSize(startSize);
// }
// });
}
private void superSetTextSize(int startSize) {
int textSize = binarySearch(startSize, (int) _maxTextSize, _sizeTester, _availableSpaceRect);
super.setTextSize(TypedValue.COMPLEX_UNIT_PX, textSize);
}
private int binarySearch(final int start, final int end, final SizeTester sizeTester, final RectF availableSpace) {
int lastBest = start, lo = start, hi = end - 1, mid;
while (lo <= hi) {
mid = lo + hi >>> 1;
final int midValCmp = sizeTester.onTestSize(mid, availableSpace);
if (midValCmp < 0) {
lastBest = lo;
lo = mid + 1;
} else if (midValCmp > 0) {
hi = mid - 1;
lastBest = hi;
} else return mid;
}
// make sure to return last best
// this is what should always be returned
return lastBest;
}
@Override
protected void onTextChanged(final CharSequence text, final int start, final int before, final int after) {
super.onTextChanged(text, start, before, after);
adjustTextSize();
}
@Override
protected void onSizeChanged(final int width, final int height, final int oldwidth, final int oldheight) {
super.onSizeChanged(width, height, oldwidth, oldheight);
if (width != oldwidth || height != oldheight)
adjustTextSize();
}
}
问题
为什么会出现这种情况？我可以做什么来解决这个问题？
最佳答案
似乎可以使用支持库:
<TextView
android:layout_width="250dp" android:layout_height="wrap_content" android:background="#f00"
android:breakStrategy="balanced" android:hyphenationFrequency="none"
android:text="This is an example text" android:textSize="30dp" app:autoSizeTextType="uniform"/>
遗憾的是，它有两个缺点:
更多信息here .
关于android - 如何避免 TextView 中文本的字符换行，以自动调整文本大小？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/36954439/