How to generate Styled text for TextView while assembling string?

问题

I have a TextView that will hold a styled, multiline string. This text is generated line by line as the data is drawn from different sources bit by bit. As I grab each field, I add a Bold header to the TextView on a new line, then I add the data for that field in italics on a new line.

Example formatting:

Due Date
July 22, 2010
Course
CSC 350

I could set the styling like this:

Spannable str = (Spannable) textview.getText();

str.setSpan(new StyleSpan(android.graphics.Typeface.Bold), 0, 8, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
str.setSpan(new StyleSpan(android.graphics.Typeface.Italic), 8, 21, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
str.setSpan(new StyleSpan(android.graphics.Typeface.Bold), 21, 27, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
str.setSpan(new StyleSpan(android.graphics.Typeface.Italic), 27, 33, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

But that requires knowing the length of each section of text at runtime which is simply unmanageable since there is a variable number of data fields that could be added to the textview.

How can I add the styling as I'm adding each piece of text instead of after all the text has been added?

回答1:

Mark your string up with <b> and <i> tags as appropriate and then use the Html.fromHtml(String) to return the Spannable you are looking for.

回答2:

Html.fromHtml(String) carries a lot more baggage with it than the more light weight SpannableString classes. Whenever possible I would recommend that you avoid fromHtml to style a string.

In your case you could build the string with SpannableStringBuilder and then set the TextView text with the final styled string.

// set the text
SpannableString s1 = new SpannableString("Due Date\n");
SpannableString s2 = new SpannableString("July 22, 2010\n");
SpannableString s3 = new SpannableString("Course\n");
SpannableString s4 = new SpannableString("CSC 350\n");

// set the style
s1.setSpan(new StyleSpan(Typeface.BOLD), 0, s1.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
s2.setSpan(new StyleSpan(Typeface.ITALIC), 0, s2.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
s3.setSpan(new StyleSpan(Typeface.BOLD), 0, s3.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
s4.setSpan(new StyleSpan(Typeface.ITALIC), 0, s4.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);

// build the string
SpannableStringBuilder builder = new SpannableStringBuilder();
builder.append(s1);
builder.append(s2);
builder.append(s3);
builder.append(s4);

// set the text view with the styled text
textView.setText(builder);

I set the text and styles one by one but in real usage this could easily be done in a loop. Here is the result:

回答3:

you can use this:

textview.setTypeface(null, Typeface.BOLD_ITALIC);

回答4:

You can set a Spannable as the text of the TextView. That way you can create your text first, add style info when needed, and put that into the TextView as appropriate.

回答5:

You should check how HTML class does it. I would parse the input and generate the spannable on the fly.

回答6:

I know this question is somewhat old but as it is the top on google, I'd like to throw in the developer page as a good resource for this. The bottom contains suggestions for helper methods to style your text programatically.

来源：https://stackoverflow.com/questions/3233657/how-to-generate-styled-text-for-textview-while-assembling-string

标签

android

coding-style

textview