在Android中的TextView中对齐文本 [英] Justifying text inside a TextView in android
问题描述
因此，正如您大多数人所知，Android的TextView中没有文字可作为理由.因此，我构建了一个自定义TextView来解决此问题.但是，由于某些原因，有时标点符号会在某些设备中由于某种原因而中断.我在LG G3和模拟器(运行最新版本的Nexus 4)和逗号"上进行了测试，例如，它打破了LG G3的理由，但没有在模拟器上.
So, as most of you know, there is no text justifying inside a TextView in Android. So, I built a custom TextView to get around the problem. However, for some reason, sometimes punctuation marks break the line for some reason in some devices. I tested on an LG G3 and emulator (Nexus 4 running latest version) and a comma "," for instance breaks the justification on the LG G3 but not on the emulator.
如果我添加的填充开始和结束(或左右)至少为2，则此问题已解决.在我看来，这很武断.
If I add a Padding start and end (or left and right) of at least 2, the problem is solved. This looks very arbitrary to me.
基本上，我的逻辑是为了证明文本的正确性，我需要知道TextView本身的宽度，将文本构造为最大长度的行.然后，通过找到行中的空格数和剩余的空白空间，根据剩余的像素(或视图中的空格)拉伸要缩放的"(空格)字符.
Basically, my logic was that in order to justify the text, I would need to know the width of the TextView itself, construct the text into lines that are at maximum that length. Then, by finding the number of spaces in the line and the remaining empty space, stretch the " " (space) characters to be scaled according to remaining pixels (or, space in the view).
它几乎完美地工作，并且在大多数情况下，它也支持RTL文本.
It works almost perfectly, and most of the time it supports RTL text as well.
这是一些带有和不带有冒犯性标记的文本图片(一个简单的lorem即时补充)(第一个在运行7.1.1的模拟器nexus 4上，第二个在运行v5.0的LG G3上)
here're some pictures of the text (a simple lorem impsum) with and without the offending marks (first one is on emulator nexus 4 running 7.1.1, second one is on LG G3 running v5.0)
代码如下:
public class DTextView extends AppCompatTextView {
private boolean justify;
public DTextView(Context context) {
super(context);
}
public DTextView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init(attrs);
}
public DTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(attrs);
}
private void setJustify(boolean justify) {
this.justify = justify;
if (justify) {
justify();
}
}
private void init(@Nullable AttributeSet attrs) {
TypedArray ta = getContext().obtainStyledAttributes(attrs, R.styleable.DTextView, 0, 0);
justify = ta.getBoolean(R.styleable.DTextView_justify, false);
ta.recycle();
}
private SpannableStringBuilder justifyText() {
String[] words = getText().toString().split(" ");
setText("");
int maxLineWidth = getWidth() - getPaddingLeft() - getPaddingRight();
SpannableStringBuilder justifiedTextSpannable = new SpannableStringBuilder();
//This will build the new text with the lines rearranged so that they will have a width
//bigger than the View's own width
ArrayList<String> lines = new ArrayList<>(0);
String line = "";
for (String word : words) {
if (getWordWidth(line + word) < maxLineWidth) {
line += word + " ";
} else {
line = line.substring(0, line.length() - 1);
lines.add(line);
line = word + " ";
}
}
//Add the last line
lines.add(line);
for (int i = 0; i < lines.size() - 1; i++) {
justifiedTextSpannable.append(justifyLine(lines.get(i), maxLineWidth));
justifiedTextSpannable.append("\n");
}
justifiedTextSpannable.append(lines.get(lines.size() - 1));
return justifiedTextSpannable;
}
private SpannableString justifyLine(String line, float maxWidth) {
SpannableString sLine = new SpannableString(line);
float spaces = line.split(" ").length - 1;
float spaceCharSize = getWordWidth(" ");
float emptySpace = maxWidth - getWordWidth(line);
float newSpaceSize = (emptySpace / spaces) + spaceCharSize;
float scaleX = newSpaceSize / spaceCharSize;
for (int i = 0; i < line.length(); i++) {
if (line.charAt(i) == ' ') {
sLine.setSpan(new ScaleXSpan(scaleX), i, i + 1, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
}
}
return sLine;
}
private void justify() {
justify = false;
setText(justifyText());
invalidate();
}
private float getWordWidth(String word) {
return getPaint().measureText(word);
}
@Override
protected void onDraw(Canvas canvas) {
if (!justify)
super.onDraw(canvas);
else
justify();
}
}
我非常感谢任何可以对此有所了解的人.
I would very much appreciate anyone that can shed some light on this.
推荐答案
So, after looking a bit more at this: https://github.com/ufo22940268/android-justifiedtextview and TextView in general, I discovered that my main problem was my approach.
使用缩放"字符宽度的方法在理论上是合理的，但是这样做之后，线的宽度又发生了变化，因为看来线的宽度不是其各部分的总和.
Using the approach of scaling the width of the " " characters was sound in theory, but after doing so, the width of the line changes again, as it seems that the width of the line is NOT the sum of its parts.
我已经改变了方法，并从上面的链接中获得了灵感，所以在我的新方法中，我自己绘制每个角色，而不是绘制整个线条.如果需要对文本进行对齐(基于自定义的"justify"布尔属性)，则将绘制线条并对其进行对齐，否则将仅绘制线条.
I have changed my approach and took inspiration from the link above, and so in my new approach I draw each character by itself, instead of drawing the whole line. If the text needs to be justified (based on a custom "justify" boolean attribute) then it will draw the line and justify it, else it will just draw the line.
我现在更改了代码，因此它也支持RTL文本.我将在接下来的几天中将代码上传到某个地方.
I have changed the code now so that it also supports RTL texts. I will upload the code somewhere in the next few days.
结果如下:
代码如下:
public class DTextView extends AppCompatTextView {
private boolean justify;
private float textAreaWidth;
private float spaceCharSize;
private float lineY;
public DTextView(Context context) {
super(context);
}
public DTextView(Context context, AttributeSet attrs) {
super(context, attrs);
init(attrs);
}
public DTextView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(attrs);
}
/**
* @param attrs the attributes from the xml
* This function loads all the parameters from the xml
*/
private void init(AttributeSet attrs) {
TypedArray ta = getContext().obtainStyledAttributes(attrs, R.styleable.DTextView, 0, 0);
justify = ta.getBoolean(R.styleable.DTextView_justify, false);
ta.recycle();
}
@Override
protected void onDraw(Canvas canvas) {
drawText(canvas);
}
private void drawText(Canvas canvas) {
TextPaint paint = getPaint();
paint.setColor(getCurrentTextColor());
paint.drawableState = getDrawableState();
textAreaWidth = getMeasuredWidth() - (getPaddingLeft() + getPaddingRight());
spaceCharSize = paint.measureText(" ");
String text = getText().toString();
lineY = getTextSize();
Layout textLayout = getLayout();
if (textLayout == null)
return;
Paint.FontMetrics fm = paint.getFontMetrics();
int textHeight = (int) Math.ceil(fm.descent - fm.ascent);
textHeight = (int) (textHeight * getLineSpacingMultiplier() + textLayout.getSpacingAdd());
for (int i = 0; i < textLayout.getLineCount(); i++) {
int lineStart = textLayout.getLineStart(i);
int lineEnd = textLayout.getLineEnd(i);
float lineWidth = StaticLayout.getDesiredWidth(text, lineStart, lineEnd, paint);
String line = text.substring(lineStart, lineEnd);
if (line.charAt(line.length() - 1) == ' ') {
line = line.substring(0, line.length() - 1);
}
if (justify && i < textLayout.getLineCount() - 1) {
drawLineJustified(canvas, line, lineWidth);
} else {
canvas.drawText(line, 0, lineY, paint);
}
lineY += textHeight;
}
}
private void drawLineJustified(Canvas canvas, String line, float lineWidth) {
TextPaint paint = getPaint();
float emptySpace = textAreaWidth - lineWidth;
int spaces = line.split(" ").length - 1;
float newSpaceSize = (emptySpace / spaces) + spaceCharSize;
float charX = 0;
for (int i = 0; i < line.length(); i++) {
String character = String.valueOf(line.charAt(i));
float charWidth = StaticLayout.getDesiredWidth(character, paint);
if (!character.equals(" ")) {
canvas.drawText(character, charX, lineY, paint);
}
if (character.equals(" ") && i != line.length() - 1)
charX += newSpaceSize;
else
charX += charWidth;
}
}
}
和XML:
<il.co.drapp.views.text.DTextView
android:layout_width="match_parent"
android:inputType="textMultiLine|textNoSuggestions"
app:justify="true"
android:id="@+id/justifyText"
android:text="@string/article_dummy_text"
android:layout_height="wrap_content" />
感谢Aditya Vyas-Lakhan提供的链接
Thanks to Aditya Vyas-Lakhan for the links
这篇关于在Android中的TextView中对齐文本的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
