安卓系统中<hr>标签的使用
我有一个声明，我必须加一条水平线。但它不受android的支持，似乎有任何方法可以重新创建
使用支持的标记在android中的标记效果。
String message = "Hello <br> hai<br> I am fine <hr>";
tab.setText(Html.fromHtml(message));它显示了你好
hai
我很好
但没有水平线。
这里，"hr“的HTML标记不起作用。是否有任何方法从受支持的标记中添加hr标记效果。提前谢谢..。
回答 6
Stack Overflow用户
发布于 2017-05-03 03:51:46
Html.fromHtml()目前不支持<hr>标记，因此您需要编写实现Html.TagHandler的自己的标记处理程序。安卓系统中的TextViews是使用Spans设计的，所以我们需要创建一个Span，它也可以画一条水平线，让我们称之为HrSpan。
Java
String html = "Hello <br> hai<br> I am fine <hr> And here's another line";
HtmlTagHandler tagHandler = new HtmlTagHandler();
Spanned styledText = HtmlCompat.fromHtml(html, HtmlCompat.FROM_HTML_MODE_LEGACY, null, tagHandler);
textView.setText(styledText);HtmlTagHandler.java
public class HtmlTagHandler implements Html.TagHandler {
@Override
public void handleTag(boolean opening, String tag, Editable output, XMLReader xmlReader) {
if (tag.equals("hr")) {
handleHrTag(opening, output);
}
}
private void handleHrTag(boolean opening, Editable output) {
final String placeholder = "\n-\n";
if (opening) {
output.insert(output.length(), placeholder);
} else {
output.setSpan(new HrSpan2(), output.length() - placeholder.length(), output.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
}
}
}HrSpan.java
public class HrSpan extends ReplacementSpan {
@Override
public int getSize(@NonNull Paint paint, CharSequence text, int start, int end, @Nullable Paint.FontMetricsInt fm) {
return 0;
}
@Override
public void draw(@NonNull Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, @NonNull Paint paint) {
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(8); // 8px tall line
int middle = (top + bottom) / 2;
// Draw a line across the middle of the canvas
canvas.drawLine(0, middle, canvas.getWidth(), middle, paint);
}
}Kotlin
val html = "Hello <br> hai<br> I am fine <hr> Another line here <hr><hr>"
val tagHandler = HtmlTagHandler()
textView.text = HtmlCompat.fromHtml(html, HtmlCompat.FROM_HTML_MODE_LEGACY, null, tagHandler)class HtmlTagHandler : Html.TagHandler {
override fun handleTag(opening: Boolean, tag: String?, output: Editable?, xmlReader: XMLReader?) {
if (output == null) return
when (tag) {
"hr" -> handleHrTag(opening, output)
// Handle other tags if needed
}
}
private fun handleHrTag(opening: Boolean, output: Editable) {
val placeholder = "\n-\n" // Makes sure the HR is drawn on a new line
if (opening) {
output.insert(output.length, placeholder)
} else {
output.setSpan(HrSpan(), output.length - placeholder.length, output.length, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
}
}
}class HrSpan : ReplacementSpan() {
override fun getSize(paint: Paint, text: CharSequence?, start: Int, end: Int, fm: Paint.FontMetricsInt?) = 0
override fun draw(
canvas: Canvas, text: CharSequence?, start: Int, end: Int, x: Float, top: Int, y: Int,
bottom: Int, paint: Paint
) {
paint.style = Paint.Style.STROKE
paint.strokeWidth = 8f
// Draw line in the middle of the available space
val middle = ((top + bottom) / 2).toFloat()
canvas.drawLine(0f, middle, canvas.width.toFloat(), middle, paint)
}
}这应该会给你这样的结果。它与您的TextView的宽度相匹配，因此，如果您希望该行占用全部宽度，则将TextView宽度属性更改为match_parent。
Stack Overflow用户
发布于 2013-10-18 08:42:36
Android Html.fromHTML并不支持所有标签。
如果你想要这样的标签，我建议你用WebView代替
WebView webview = new WebView(this);
String summary = "<html><body>Sorry, <span style=\"background: red;\">Madonna</span> gave no results</body></html>";
webview.loadData(summary, "text/html", "utf-8");WebView将允许您拥有HR或任何您喜欢的标记。
Stack Overflow用户
发布于 2013-10-18 08:37:28
Android中不支持hr标记。您必须为水平线添加一个单独的视图，以背景色作为文本。
https://stackoverflow.com/questions/19444911
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