是否有可能为一个TextView内的不同文本块设置多个样式?
例如，我将文本设置如下:
tv.setText(line1 + "\n" + line2 + "\n" + word1 + "\t" + word2 + "\t" + word3);
是否可以为每个文本元素设置不同的样式?例如，行1加粗，字1斜体等。
开发者指南的常见任务和如何在Android中执行这些任务包括选择，突出显示或样式化文本部分:
// Get our EditText object.
EditText vw = (EditText)findViewById(R.id.text);
// Set the EditText's text.
vw.setText("Italic, highlighted, bold.");
// If this were just a TextView, we could do:
// vw.setText("Italic, highlighted, bold.", TextView.BufferType.SPANNABLE);
// to force it to use Spannable storage so styles can be attached.
// Or we could specify that in the XML.
// Get the EditText's internal text storage
Spannable str = vw.getText();
// Create our span sections, and assign a format to each.
str.setSpan(new StyleSpan(android.graphics.Typeface.ITALIC), 0, 7, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
str.setSpan(new BackgroundColorSpan(0xFFFFFF00), 8, 19, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
str.setSpan(new StyleSpan(android.graphics.Typeface.BOLD), 21, str.length() - 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
但这使用了文本中的显式位置编号。有更干净的方法吗?
这可能就像利用String的length()方法一样简单:
将Strings XML文件中的文本字符串拆分为许多子字符串(从Android的角度来看是一个单独的字符串)，因为你需要不同的风格，所以它可以像:str1, str2, str3(在你的情况下)，当连接在一起时，就是你使用的整个单一字符串。
然后简单地遵循“Span”方法，就像您在代码中展示的那样——但不是单个字符串，而是将所有子字符串合并为单个字符串，每个子字符串具有不同的自定义样式。
你仍然使用这些数字，但不是直接使用——它们现在不再采用硬编码形式(就像在你的代码中那样)，但它们被组合length()方法所取代(注意在str.length()之前和后面加上两颗星来代替绝对数字，以消除变化):
str.setSpan(new StyleSpan(android.graphics.Typeface.ITALIC), 0, **str.length()**, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
对于第一个字符串大小，则str.length() + 1，对于第二个字符串大小，则str.length() + str2.length()，等等，所有的子字符串，而不是例如0,7或8,19等等…
使用SpannableString是实现这一目标的好方法
我使用了几个函数使其易于应用，我将首先解释每个函数的思想，然后显示代码:
String.getAllIndexOf(pattern: String): This will search the patter on the string and return an index list of where the pattern start. Ex: given the string "abcdefabc" and I call the method passing the "abc" as the searched pattern, the method should return the list: listOf(0, 6)
The is a class to receive the pattern and a list of styles (in case you desire to apply different styles to the same pattern in sequence)
SpannableString.applyStyle(context: Context, vararg patternAndStyles: PatternAndStyles): This will apply the styles to the given patterns
现在，在代码上:
getAllIndexOf
fun String.getAllIndexOf(pattern: String): List<Int> {
val allRecordsOfText = mutableListOf<Int>()
var index = 0
while(index >= 0) {
val newStart = if (allRecordsOfText.isEmpty()) {
0
} else {
allRecordsOfText.last() + pattern.length
}
index = this.subSequence(newStart, this.length).indexOf(pattern)
if (index >= 0) {
allRecordsOfText.add(newStart + index)
}
}
return allRecordsOfText.toList()
}
Class to receive the pattern and styles
@Parcelize
class PatternAndStyles(
val pattern: String,
val styles: List<Int>
) : Parcelable
applyStyle
fun SpannableString.applyStyle(context: Context, vararg patternAndStyles: PatternAndStyles) {
for (patternStyle in patternAndStyles.toList()) {
this.toString().getAllIndexOf(patternStyle.pattern).forEachIndexed { index, start ->
val end = start + patternStyle.pattern.length
val styleIndex = if (patternStyle.styles.size > index) index else patternStyle.styles.size - 1
this.setSpan(
TextAppearanceSpan(context, patternStyle.styles[styleIndex]),
start,
end,
SPAN_EXCLUSIVE_EXCLUSIVE
)
}
}
}
How to use it in the end
val stringToApplyStyle = "abc def abc def"
val text = SpannableString(stringToApplyStyle)
text.applyStyle(
this.applicationContext,
PatternAndStyles("abc", listOf(R.style.Style1, R.style.Style2)),
PatternAndStyles("def", listOf(R.style.Style3))
)
The output:
当它被传递给样式到模式“abc”时，两者都被使用
但是在模式“def”中，第二条记录重用了列表中给出的最后一个样式
使用SpannableString而不是html标记更轻量级。它帮助我看到可视化的例子，所以这里是一个补充的答案。
这是一个单一的TextView。
// set the text
SpannableString s1 = new SpannableString("bold\n");
SpannableString s2 = new SpannableString("italic\n");
SpannableString s3 = new SpannableString("foreground color\n");
SpannableString s4 = new SpannableString("background color\n");
SpannableString s5 = new SpannableString("underline\n");
SpannableString s6 = new SpannableString("strikethrough\n");
SpannableString s7 = new SpannableString("bigger\n");
SpannableString s8 = new SpannableString("smaller\n");
SpannableString s9 = new SpannableString("font\n");
SpannableString s10 = new SpannableString("URL span\n");
SpannableString s11 = new SpannableString("clickable span\n");
SpannableString s12 = new SpannableString("overlapping spans\n");
// set the style
int flag = Spanned.SPAN_EXCLUSIVE_EXCLUSIVE;
s1.setSpan(new StyleSpan(Typeface.BOLD), 0, s1.length(), flag);
s2.setSpan(new StyleSpan(Typeface.ITALIC), 0, s2.length(), flag);
s3.setSpan(new ForegroundColorSpan(Color.RED), 0, s3.length(), flag);
s4.setSpan(new BackgroundColorSpan(Color.YELLOW), 0, s4.length(), flag);
s5.setSpan(new UnderlineSpan(), 0, s5.length(), flag);
s6.setSpan(new StrikethroughSpan(), 0, s6.length(), flag);
s7.setSpan(new RelativeSizeSpan(2), 0, s7.length(), flag);
s8.setSpan(new RelativeSizeSpan(0.5f), 0, s8.length(), flag);
s9.setSpan(new TypefaceSpan("monospace"), 0, s9.length(), flag);
s10.setSpan(new URLSpan("https://developer.android.com"), 0, s10.length(), flag);
s11.setSpan(new ClickableSpan() {
@Override
public void onClick(View widget) {
Toast.makeText(getApplicationContext(), "Span clicked", Toast.LENGTH_SHORT).show();
}
}, 0, s11.length(), flag);
s12.setSpan(new ForegroundColorSpan(Color.RED), 0, 11, flag);
s12.setSpan(new BackgroundColorSpan(Color.YELLOW), 4, s12.length(), flag);
s12.setSpan(new UnderlineSpan(), 4, 11, flag);
// build the string
SpannableStringBuilder builder = new SpannableStringBuilder();
builder.append(s1);
builder.append(s2);
builder.append(s3);
builder.append(s4);
builder.append(s5);
builder.append(s6);
builder.append(s7);
builder.append(s8);
builder.append(s9);
builder.append(s10);
builder.append(s11);
builder.append(s12);
// set the text view with the styled text
textView.setText(builder);
// enables clicking on spans for clickable span and url span
textView.setMovementMethod(LinkMovementMethod.getInstance());
进一步的研究
解释SPAN_EXCLUSIVE_EXCLUSIVE等Span标志的含义
Android Spanned, SpannedString, Spannable, SpannableString和CharSequence
跨度类型
这个例子最初的灵感来自这里。
