Android開發-TextViev（一）

TextView是Android中最常用的控制元件之一，大部分時候大家只使用了一些簡單的功能。比如：顯示一個字串，顯示一個HTML片段等。我們一起來詳細瞭解一下TextView。

android:autoLink

Constant	Value	Description
none	0x00	Match no patterns (default).
web	0x01	Match Web URLs.
email	0x02	Match email addresses.
phone	0x04	Match phone numbers.
map	0x08	Match map addresses.
all	0x0f	Match all patterns (equivalent to web|email|phone|map).

xml片段

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:autoLink="phone"
        android:text="13888888888" />

執行效果

Tips

點選電話號碼後跳轉到撥號頁面，如果不是電話號碼則無效。

原始碼分析

    /**
     *  掃描提供的常量，新增對應的link。（這裡以phone為例）
     */
    public static final boolean addLinks(Spannable text, int mask) {
        if (mask == 0) {
            return false;
        }

        URLSpan[] old = text.getSpans(0, text.length(), URLSpan.class);

        for (int i = old.length - 1; i >= 0; i--) {
            text.removeSpan(old[i]);
        }

        ArrayList<LinkSpec> links = new ArrayList<LinkSpec>();

        // 這裡只保留了PHONE型別

        if ((mask & PHONE_NUMBERS) != 0) {
            gatherTelLinks(links, text);
        }

        pruneOverlaps(links);

        if (links.size() == 0) {
            return false;
        }

        for (LinkSpec link: links) {
            applyLink(link.url, link.start, link.end, text);
        }

        return true;
    }

    /**
     * 在URL中增加"tel:"，點選後跳轉到撥打電話頁面
     */
    private static final void gatherTelLinks(ArrayList<LinkSpec> links, Spannable s) {
        PhoneNumberUtil phoneUtil = PhoneNumberUtil.getInstance();
        Iterable<PhoneNumberMatch> matches = phoneUtil.findNumbers(s.toString(),
                Locale.getDefault().getCountry(), Leniency.POSSIBLE, Long.MAX_VALUE);
        for (PhoneNumberMatch match : matches) {
            LinkSpec spec = new LinkSpec();
            spec.url = "tel:" + PhoneNumberUtils.normalizeNumber(match.rawString());
            spec.start = match.start();
            spec.end = match.end();
            links.add(spec);
        }
    }

android:autoText

從API3以後不建議使用android:autoText，使用inputType替代。

android:breakStrategy

Constant	Value	Description
simple	0	Line breaking uses simple strategy.
high_quality	1	Line breaking uses high-quality strategy, including hyphenation.
balanced	2	Line breaking strategy balances line lengths.

android:bufferType

Constant	Value	Description
normal	0	Can return any CharSequence, possibly a Spanned one if the source text was Spanned.
spannable	1	Can only return Spannable.
editable	2	Can only return Spannable and Editable.

待續···