setSpan 冲突问题
参考
http://stackoverflow.com/questions/29505622/spannablestringbuilder-set-clickablespan-more-than-once-cant-click
http://stackoverflow.com/questions/13118278/why-cant-use-the-same-span-object-to-setspan-above-twice
http://stackoverflow.com/questions/20077457/spannablestring-changes-color-first-time-but-not-when-reused
http://www.jianshu.com/p/be0d79b9d5e6
项目中要求做几个链接，点击跳转到不同的h5页面. 根据效果图，决定使用富文本做。
先贴修改后的代码：
自定义一个ClickableSpan
public class CustomUrlSpan extends ClickableSpan {
private String url;
private String title;
public CustomUrlSpan( String url, String title) {
this.url = url;
this.title = title;
}
@Override
public void onClick(View widget) {
Intent intent = new Intent(ContextUtils.getContext(), WebViewActivity.class).setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.putExtra(Constant.WEB_URL, url);
intent.putExtra(Constant.WEB_TITLE,title);
ContextUtils.getContext().startActivity(intent);
}
}
根据不同的航班，拼接不同的协议文本放到textview
StringBuffer stringBuffer = new StringBuffer();
stringBuffer.append("已阅读并同意<a href='" + HttpServiceConstants.FLIGHT_AIRPORT_AGREEN_CONSIGN_URL + "' > " + getActivity().getString(R.string.frm_flight_order_protocol) + " </a>");
String dot = "<font color='" + ContextCompat.getColor(ContextUtils.getContext(), R.color.txt_blue) + "'> 、 </font>";
stringBuffer.append(dot).append("<a href='" + Constant.WEB_URL_BATTERY + "' > " + getActivity().getString(R.string.frm_flight_order_protocol_battery) + " </a>");
flightCabinselTravelBinding.tvFlightProtocol.setText(HtmlUtil.fromHtml(stringBuffer.toString()));
flightCabinselTravelBinding.tvFlightProtocol.setMovementMethod(new FixedLinkMovementMethod());
CharSequence text = flightCabinselTravelBinding.tvFlightProtocol.getText();
int end = text.length();
Spannable spannable = (Spannable) text;
URLSpan[] urlSpans = spannable.getSpans(0, end, URLSpan.class);
if (urlSpans.length == 0) {
return;
}
SpannableStringBuilder spannableStringBuilder = new SpannableStringBuilder(text);
// 循环遍历并拦截 所有http://开头的链接
for (URLSpan uri : urlSpans) {
final String url = uri.getURL();
if (url.indexOf("http") == 0) {
CustomUrlSpan customUrlSpan = null;
//托运协议
if (url.equals(HttpServiceConstants.FLIGHT_AIRPORT_AGREEN_CONSIGN_URL)) {
customUrlSpan = new CustomUrlSpan(url, getActivity().getString(R.string.frm_flight_order_protocol));
}
//西部
else if (url.equals(Constant.WEB_URL_WEST)) {
customUrlSpan = new CustomUrlSpan(url, getActivity().getString(R.string.frm_flight_order_protocol_west));
}
//深圳航空
else if (url.equals(Constant.WEB_URL_SZ)) {
customUrlSpan = new CustomUrlSpan(url, getActivity().getString(R.string.frm_flight_order_protocol_sz));
}
//锂电池及危险品须知
else if (url.equals(Constant.WEB_URL_BATTERY)) {
customUrlSpan = new CustomUrlSpan(url, getActivity().getString(R.string.frm_flight_order_protocol_battery));
}
if (customUrlSpan != null) {
// The original URLSpan needs to be removed to block the behavior of browser opening
spannableStringBuilder.removeSpan(uri);
spannableStringBuilder.setSpan(CharacterStyle.wrap(customUrlSpan), spannable.getSpanStart(uri),
spannable.getSpanEnd(uri), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
}
}
}
flightCabinselTravelBinding.tvFlightProtocol.setText(spannableStringBuilder);
开发过程中遇到的问题：
1、点击文字链接跳转到了系统自带浏览器当中，CustomUrlSpan的点击事件并没有执行
2、在webviewActivity中打开链接，返回退出该富文本页面。再次进入，更改后的协议文本拼接没错，但textView展示出来的文本还是之前的文本，并没有根据拼接内容而改变。
问题1 解决：
setSpan 的时候，需要先去掉原本的UrlSpan ,阻止链接在系统的浏览器打开。
// The original URLSpan needs to be removed to block the behavior of browser opening
spannableStringBuilder.removeSpan(uri);
问题2 解决：
先要了解 <b>LinkMovementMethod</b> 、 <b>SpannableStringBuilder</b>、<b>CharacterStyle.wrap()</b>
LinkMovementMethod
A movement method that traverses links in the text buffer and scrolls if necessary. Supports clicking on links with DPad Center or Enter.
简单来说，就是让链接与滚动生效。
富文本的点击事件会分发到这个对象里面，那么我们可以在onTouchEvent()中来处理这个点击事件。
代码中过滤出了ClickableSpan，执行click事件
public class FixedLinkMovementMethod extends LinkMovementMethod {
@Override
public boolean onTouchEvent(TextView widget, Spannable buffer, MotionEvent event) {
int action = event.getAction();
if (action == MotionEvent.ACTION_UP ||
action == MotionEvent.ACTION_DOWN) {
int x = (int) event.getX();
int y = (int) event.getY();
x -= widget.getTotalPaddingLeft();
y -= widget.getTotalPaddingTop();
x += widget.getScrollX();
y += widget.getScrollY();
Layout layout = widget.getLayout();
int line = layout.getLineForVertical(y);
int off = layout.getOffsetForHorizontal(line, x);
CharacterStyle[] candidates = buffer.getSpans(off, off, CharacterStyle.class);
ClickableSpan clickableSpan = null;
for (CharacterStyle characterStyle : candidates) {
if (characterStyle.getUnderlying() instanceof ClickableSpan) {
clickableSpan = (ClickableSpan) characterStyle.getUnderlying();
break;
}
}
if (clickableSpan != null) {
if (action == MotionEvent.ACTION_UP) {
clickableSpan.onClick(widget);
} else if (action == MotionEvent.ACTION_DOWN) {
Selection.setSelection(buffer,
buffer.getSpanStart(clickableSpan),
buffer.getSpanEnd(clickableSpan));
}
return true;
} else {
Selection.removeSelection(buffer);
}
}
return super.onTouchEvent(widget, buffer, event);
}
}
SpannableStringBuilder
You can't reuse the same span multiple times. Even if the span is exactly the same, you need to create a unique span for each section of the string you are wanting to change.
不要多次重复使用相同的span , 最好创建一个唯一的span，避免出现之前的span被改变。
When you pass same span by setSpan method, it will check if spans array have same one and replace old start and end value by news.
当使用setSpan方法的时候，方法中会判断是否存在一个相同的spans array ，start 到 end 的值会被最新的替换。
也就是说，复用span的话，之前的span可能会被最新的span改变。
/* package */ void setSpan(Object what, int start, int end, int flags) {
...
for (int i = 0; i < count; i++) {
if (spans[i] == what) {
int ostart = mSpanStarts[i];
int oend = mSpanEnds[i];
if (ostart > mGapStart)
ostart -= mGapLength;
if (oend > mGapStart)
oend -= mGapLength;
mSpanStarts[i] = start;
mSpanEnds[i] = end;
mSpanFlags[i] = flags;
if (send) sendSpanChanged(what, ostart, oend, nstart, nend);
return;
}
}
...
}
CharacterStyle.wrap()
CharacterStyle是个抽象类，字符级别的Span都需要继承这个类
CharacterStyle拥有很多子类（BackgroundColorSpan，ClickableSpan，ImageSpan，TypefaceSpan等）
一个CharacterStyle类型的Span只能给一个Spaned片段使用，如果想这个Span给多个片段使用可以使用wrap方法。
其实就是复制了一个CharacterStyle。
public static CharacterStyle wrap(CharacterStyle cs) {
if (cs instanceof MetricAffectingSpan) {
return new MetricAffectingSpan.Passthrough((MetricAffectingSpan) cs);
} else {
return new Passthrough(cs);
}
}
if you use CharacterStyle.wrap() your span is no longer a ClickableSpan instance, but a CharacterStyle.Passthrough instance instead. Therefore getSpans() does not return it anymore and it's no longer clickable.
如果使用了CharacterStyle.wrap() ， 那么span不会是一个ClickableSpan ，也就是说点击事件会失效。
A given CharacterStyle can only applied to a single region of a given Spanned. If you need to attach the same CharacterStyle to multiple regions, you can use this method to wrap it with a new object that will have the same effect but be a distinct object so that it can also be attached without conflict.
有多个片段的时候使用，解决attached的冲突问题。
原来如此，是因为没有使用CharacterStyle.wrap()而导致的问题。最后再自定义一个LinkMovementMethod处理click事件，问题就解决了。
