TextView富文本学习二（获取html代码片段中的超链接地址，设置点击事件，并设置连接样式）

1 利用SpannableStringBuilder获取存在的Span

/**
* Return an array of the spans of the specified type that overlap
* the specified range of the buffer. The kind may be Object.class to get
* a list of all the spans regardless of type.
*/
@SuppressWarnings(“unchecked”)
public T[] getSpans(int queryStart, int queryEnd, @Nullable Class kind) {
return getSpans(queryStart, queryEnd, kind, true);
}

getSpans可以获取SpannableStringBuilder中被设置的Span数组，参数说明:
queryStart：开始位置
queryEnd:结束位置
kind：span对应的Class

例子：

              setContentView(R.layout.activity_urlspan_click);
        mTextView = findViewById(R.id.textview);

        SpannableStringBuilder spannableStringBuilder1 = new SpannableStringBuilder("测试富文本样式设");
        ForegroundColorSpan fspan1 = new ForegroundColorSpan(Color.RED);
        spannableStringBuilder1.setSpan(fspan1,4,8, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
        SpannableString textSpanned1 = new SpannableString("置字体颜色设置");
        ForegroundColorSpan fspan2 = new ForegroundColorSpan(Color.BLUE);
        textSpanned1.setSpan(fspan2,0,textSpanned1.length(), Spanned.SPAN_INCLUSIVE_INCLUSIVE);
        spannableStringBuilder1.append(textSpanned1);
        mTextView.setText(spannableStringBuilder1);
        ForegroundColorSpan[] spans =  spannableStringBuilder1.getSpans(0, spannableStringBuilder1.length(), ForegroundColorSpan.class);
        System.out.println("========spans.length========"+spans.length);

        System.out.println("========SpanStart========"+spannableStringBuilder1.getSpanStart(spans[0]));
        System.out.println("========SpanEnd========"+spannableStringBuilder1.getSpanEnd(spans[0]));
        System.out.println("========SpanFlags========"+spannableStringBuilder1.getSpanFlags(spans[0]));

        System.out.println("========SpanStart========"+textSpanned1.getSpanStart(spans[1]));
        System.out.println("========SpanEnd========"+textSpanned1.getSpanEnd(spans[1]));
        System.out.println("========SpanFlags========"+textSpanned1.getSpanFlags(spans[1]));

result：
========spans.length========2
========SpanStart========4
========SpanEnd=======15
========SpanFlags=======18
========SpanStart=======0
========SpanEnd=======7
========SpanFlags=======18

获取到两个设置的ForegroundColorSpan，然后可以利用获取到的ForegroundColorSpan得到调用setSpan时的信息。

2 利用URLSpan和ClickableSpan给html代码片段超链接设置点击

给html中的超链接设置点击事件：

public class URLSpanClickActivity extends AppCompatActivity {

    private TextView mTextView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_urlspan_click);
        mTextView = findViewById(R.id.textview);
        /*SpannableStringBuilder spannableStringBuilder1 = new SpannableStringBuilder("测试富文本样式设");
        ForegroundColorSpan fspan1 = new ForegroundColorSpan(Color.RED);
        spannableStringBuilder1.setSpan(fspan1,4,8, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
        SpannableString textSpanned1 = new SpannableString("置字体颜色设置");
        ForegroundColorSpan fspan2 = new ForegroundColorSpan(Color.BLUE);
        textSpanned1.setSpan(fspan2,0,textSpanned1.length(), Spanned.SPAN_INCLUSIVE_INCLUSIVE);
        spannableStringBuilder1.append(textSpanned1);
        mTextView.setText(spannableStringBuilder1);
        ForegroundColorSpan[] spans =  spannableStringBuilder1.getSpans(0, spannableStringBuilder1.length(), ForegroundColorSpan.class);
        System.out.println("========spans.length========"+spans.length);

        System.out.println("========SpanStart========"+spannableStringBuilder1.getSpanStart(spans[0]));
        System.out.println("========SpanEnd========"+spannableStringBuilder1.getSpanEnd(spans[0]));
        System.out.println("========SpanFlags========"+spannableStringBuilder1.getSpanFlags(spans[0]));

        System.out.println("========SpanStart========"+textSpanned1.getSpanStart(spans[1]));
        System.out.println("========SpanEnd========"+textSpanned1.getSpanEnd(spans[1]));
        System.out.println("========SpanFlags========"+textSpanned1.getSpanFlags(spans[1]));*/
        mTextView.setMovementMethod(LinkMovementMethod.getInstance());
        String originalStr = "url 跳转的测试 
" +
                "百度 
\n" +
                "W3School";
        CharSequence stringBuilder = getClickableHtml(originalStr);
        mTextView.setText(stringBuilder);

    }

    private CharSequence getClickableHtml(String html) {
        Spanned spannedHtml = null;
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            spannedHtml = Html.fromHtml(html, Html.FROM_HTML_MODE_COMPACT);
        } else {
            spannedHtml = Html.fromHtml(html);
        }
        SpannableStringBuilder clickableBuilder = new SpannableStringBuilder(spannedHtml);
        URLSpan[] urls = clickableBuilder.getSpans(0, spannedHtml.length(), URLSpan.class);
        if (urls.length == 0){
            return html.replace("\\n", "\n").replace("\\r", "\r");
        }
        //获取所有的URL
        for (final URLSpan span : urls) {
            setLinkClickable(clickableBuilder, span);
        }
        return clickableBuilder;
    }


    //必须设置setMovementMethod(LinkMovementMethod.getInstance());ClickableSpan才会生效
    private void setLinkClickable(final SpannableStringBuilder clickableHtmlBuilder, final URLSpan urlSpan) {
        int start = clickableHtmlBuilder.getSpanStart(urlSpan);
        int end = clickableHtmlBuilder.getSpanEnd(urlSpan);
        int flags = clickableHtmlBuilder.getSpanFlags(urlSpan);
        ClickableSpan clickableSpan = new ClickableSpan() {

            public void onClick(View view) {
                //可以获取html代码中的url地址，然后根据需要跳转特定页面
                String url = urlSpan.getURL();
                Toast.makeText(URLSpanClickActivity.this,"跳转url"+url,Toast.LENGTH_SHORT).show();
            }
            public void updateDrawState(TextPaint ds) {
                //设置字体颜色
                ds.setColor(Color.RED);
                //去掉下划线
                ds.setUnderlineText(false);
            }

        };
        clickableHtmlBuilder.setSpan(clickableSpan, start, end, flags);
    }
}