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如何利用Android仿微博正文鏈接交互效果_Android

作者：笑慢 ? 更新時(shí)間： 2022-06-22 編程語(yǔ)言

前言

社區(qū)內(nèi)容經(jīng)常會(huì)有插入鏈接的需要，這時(shí)就產(chǎn)生了對(duì)鏈接的UI和點(diǎn)擊交互的需求，我們?cè)谖⒉┲幸步?jīng)常會(huì)在列表頁(yè)面和詳情頁(yè)面看到。下邊我們就此功能分析一下具體實(shí)現(xiàn)。

一、鏈接的匹配和顯示交互

首先我們先分析一下鏈接的組成部分，可以肯定的是需要一個(gè)顯示的標(biāo)題，我們可能會(huì)對(duì)這個(gè)標(biāo)題在UI表現(xiàn)上做些處理（常見的是一個(gè)鏈接的標(biāo)志和設(shè)置不同的顏色）來提示和吸引用戶的注意，另外還需要點(diǎn)擊時(shí)跳轉(zhuǎn)的鏈接，這條鏈接可以是內(nèi)部也可以是外部（這就屬于業(yè)務(wù)的需求）。關(guān)于鏈接的匹配方式可能會(huì)有不同的方案，我們這里選擇了使用a標(biāo)簽的匹配方式，也就是接口會(huì)把鏈接的數(shù)據(jù)以a標(biāo)簽的形式給我們，客戶端來進(jìn)行匹配數(shù)據(jù)，下邊我們簡(jiǎn)單的舉一個(gè)例子，接口返回?cái)?shù)據(jù)如下：

"你說的<a     >我是鏈接</a>11111<a     >我也是鏈接</a>好開心啊，哈哈哈哈"

接下來我們對(duì)數(shù)據(jù)的處理：

/**
 * 匹配a標(biāo)簽直接插入鏈接
 */
suspend fun computeLenFilterLink(text: String, mContext: Context): SpannableStringBuilder =
    withContext(Dispatchers.Default) {

        var strings = SpannableStringBuilder(text)
        val pattern = "<a \s*href\s*=\s*(?:.*?)>(.*?)</a\s*>"
        val p = Pattern.compile(pattern)
        val matcher = p.matcher(strings)
        while (matcher.find()) {
            val str = matcher.group()
            val linkTitle = matcher.group(1) ?: ""

            //a標(biāo)簽鏈接正則匹配
            val patternUrlString =
                "\s*(?i)href\s*=\s*("([^"]*")|'[^']*'|([^'">\s]+))"
            val patternUrl = Pattern.compile(
                patternUrlString,
                Pattern.CASE_INSENSITIVE
            )
            //鏈接url
            val matcherUrL = patternUrl.matcher(strings)
            var linkUrl = ""
            while (matcherUrL.find()) {
                linkUrl = matcherUrL.group()
                linkUrl = linkUrl.replace("href\s*=\s*(['|"]*)".toRegex(), "")
                linkUrl = linkUrl.replace("['|"]".toRegex(), "")
                linkUrl = linkUrl.trim { it <= ' ' }
                break
            }
            //設(shè)置顏色
            val sb = SpannableString("#$linkTitle")
            sb.setSpan(
                ForegroundColorSpan(
                    ContextCompat.getColor(mContext, R.color.link_color)
                ), 0,
                sb.length,
                Spanned.SPAN_INCLUSIVE_INCLUSIVE
            )

            sb.setSpan(
                object : MyLinkClickSpan(mContext) {
                    override fun onSpanClick(widget: View?) {
                        //鏈接跳轉(zhuǎn)
                        Toast.makeText(mContext, "點(diǎn)擊鏈=$linkUrl", Toast.LENGTH_SHORT).show()

                    }
                },
                0, sb.length, Spanned.SPAN_INCLUSIVE_INCLUSIVE
            )
            val start = strings.indexOf(str)
            strings.delete(start, start + str.length)
            //插入鏈接
            strings.insert(start, sb)
        }
        return@withContext strings
    }

這里我們是用正則匹配的方式取出鏈接的標(biāo)題和跳轉(zhuǎn)鏈接，然后設(shè)置鏈接的標(biāo)志和顏色替換原來的a標(biāo)簽插入正文數(shù)據(jù)中。接下來就是設(shè)置顯示的數(shù)據(jù)：

val string = "你說的<a     >我是鏈接</a>11111<a     >我也是鏈接</a>好開心啊，哈哈哈哈"
lifecycleScope.launch {
    val contentString = LinkCheckHelper.computeLenFilterLink(string,this@MainActivity)
    tvLink.text = contentString
}

二、鏈接的點(diǎn)擊交互

參考微博的交互效果我們會(huì)發(fā)現(xiàn)當(dāng)我們觸摸鏈接內(nèi)容時(shí)其背景會(huì)由透明變?yōu)殒溄游淖值念伾种柑饡r(shí)又置回透明。細(xì)心的你肯定發(fā)現(xiàn)我們?cè)趧偛沛溄訑?shù)據(jù)的插入時(shí)設(shè)置了MyLinkClickSpan做了對(duì)鏈接點(diǎn)擊的處理，那么背景顏色的改變就要在ClickSpan中的 updateDrawState(ds: TextPaint)方法中進(jìn)行處理，代碼如下：

class MyLinkClickSpan(private val context: Context) :
    ClickableSpan(), IPressedSpan {
    private var isPressed = false
    abstract fun onSpanClick(widget: View?)
    override fun onClick(widget: View) {
        if (ViewCompat.isAttachedToWindow(widget)) {
            onSpanClick(widget)
        }
    }

    override fun setPressed(pressed: Boolean) {
        isPressed = pressed
    }

    override fun updateDrawState(ds: TextPaint) {
        if (isPressed) {
            ds.bgColor = ContextCompat.getColor(context, R.color.link_bg_color)
        } else {
            ds.bgColor = ContextCompat.getColor(context, android.R.color.transparent)
        }
        ds.isUnderlineText = false
    }
}

我們發(fā)現(xiàn)背景顏色的變化是需要對(duì)手指按下和抬起分別進(jìn)行處理，所以這時(shí)不可避免的我們就要對(duì)觸摸事件進(jìn)行處理：

class LinkTextView(context: Context, attrs: AttributeSet?) :
    AppCompatTextView(context, attrs) {
    private var mPressedSpan: IPressedSpan? = null
    init {
        isFocusable = false
        isLongClickable = false
//        有鏈接點(diǎn)擊需求不設(shè)置則點(diǎn)擊無效
        movementMethod = MyLinkMovementMethod.instance
        highlightColor = Color.TRANSPARENT
    }

    override fun onTouchEvent(event: MotionEvent): Boolean {
        val text = text
        val spannable = Spannable.Factory.getInstance().newSpannable(text)
        if (event.action == MotionEvent.ACTION_DOWN) {
            //按下時(shí)記下clickSpan
            mPressedSpan = getPressedSpan(this, spannable, event)
        }
        return if (mPressedSpan != null) {
            //如果有clickSpan就走M(jìn)yLinkMovementMethod的onTouchEvent
            MyLinkMovementMethod.instance.onTouchEvent(this, getText() as Spannable, event)
        } else {
            super.onTouchEvent(event)
        }
    }

    private fun getPressedSpan(
        textView: TextView, spannable: Spannable,
        event: MotionEvent
    ): IPressedSpan? {
        var mTouchSpan: IPressedSpan? = null
        var x = event.x.toInt()
        var y = event.y.toInt()
        x -= textView.totalPaddingLeft
        x += textView.scrollX
        y -= textView.totalPaddingTop
        y += textView.scrollY
        val layout = textView.layout
        val line = layout.getLineForVertical(y)
        try {
            var off = layout.getOffsetForHorizontal(line, x.toFloat())
            if (x < layout.getLineLeft(line) || x > layout.getLineRight(line)) {
                // 實(shí)際上沒點(diǎn)到任何內(nèi)容
                off = -1
            }
            val linkSpans =
                spannable.getSpans(off, off, IPressedSpan::class.java)
            if (!linkSpans.isNullOrEmpty()) {
                mTouchSpan = linkSpans[0]
            }
            return mTouchSpan
        } catch (e: IndexOutOfBoundsException) {
            Log.d(this.toString(), "getPressedSpan", e)
        }
        return null
    }
}
class MyLinkMovementMethod : LinkMovementMethod() {
    override fun onTouchEvent(widget: TextView, buffer: Spannable, event: MotionEvent): Boolean {
        return (sHelper.onTouchEvent(widget, buffer, event))
    }

    companion object {
        val instance: MyLinkMovementMethod
            get() {
                if (sInstance == null) {
                    sInstance = MyLinkMovementMethod()
                }
                return sInstance as MyLinkMovementMethod
            }
        private var sInstance: MyLinkMovementMethod? = null
        private val sHelper = SpanClickHelper()
    }
}
class SpanClickHelper {
    private var mPressedSpan: IPressedSpan? = null

    fun onTouchEvent(
        textView: TextView,
        spannable: Spannable,
        event: MotionEvent
    ): Boolean {
        return when (event.action) {
            MotionEvent.ACTION_DOWN -> {
                mPressedSpan = getPressedSpan(textView, spannable, event)
                if (mPressedSpan != null) {
                    //手指按下 設(shè)置按下為true，修改對(duì)應(yīng)的鏈接文字背景顏色
                    mPressedSpan!!.setPressed(true)
                    //設(shè)置選中區(qū)域
                    Selection.setSelection(
                        spannable, spannable.getSpanStart(mPressedSpan),
                        spannable.getSpanEnd(mPressedSpan)
                    )
                }

                mPressedSpan != null
            }
            MotionEvent.ACTION_MOVE -> {
                val touchedSpan = getPressedSpan(textView, spannable, event)
                if (mPressedSpan != null && touchedSpan != mPressedSpan) {
                    //手指移動(dòng)時(shí) 設(shè)置按下為false，對(duì)應(yīng)的鏈接文字背景顏色置回透明
                    mPressedSpan!!.setPressed(false)
                    mPressedSpan = null
                    //移除選中區(qū)域
                    Selection.removeSelection(spannable)
                }
                mPressedSpan != null
            }
            MotionEvent.ACTION_UP -> {
                var touchSpanHint = false
                if (mPressedSpan != null) {
                    touchSpanHint = true
                    //手指抬起時(shí) 設(shè)置按下為false，對(duì)應(yīng)的鏈接文字背景顏色置回透明
                    mPressedSpan!!.setPressed(false)
                    //傳遞點(diǎn)擊事件回調(diào)
                    mPressedSpan!!.onClick(textView)
                }
                mPressedSpan = null
                Selection.removeSelection(spannable)
                touchSpanHint
            }
            else -> {
                if (mPressedSpan != null) {
                    //其它收拾 都設(shè)置按下為false,對(duì)應(yīng)的鏈接文字背景顏色置回透明
                    mPressedSpan!!.setPressed(false)
                }
                //移除選中區(qū)域
                Selection.removeSelection(spannable)
                false
            }
        }
    }

    /**
     * 判斷手指是否點(diǎn)擊在鏈接上
     */
    private fun getPressedSpan(
        textView: TextView,
        spannable: Spannable,
        event: MotionEvent
    ): IPressedSpan? {
        var x = event.x.toInt()
        var y = event.y.toInt()
        x -= textView.totalPaddingLeft
        y -= textView.totalPaddingTop
        x += textView.scrollX
        y += textView.scrollY
        val layout = textView.layout
        val line = layout.getLineForVertical(y)

        try {
            var off = layout.getOffsetForHorizontal(line, x.toFloat())
            if (x < layout.getLineLeft(line) || x > layout.getLineRight(line)) {
                // 實(shí)際上沒點(diǎn)到任何內(nèi)容
                off = -1
            }
            val link = spannable.getSpans(
                off, off,
                IPressedSpan::class.java
            )
            var touchedSpan: IPressedSpan? = null
            if (link.isNotEmpty()) {
                touchedSpan = link[0]
            }
            return touchedSpan
        } catch (e: IndexOutOfBoundsException) {
            Log.d(this.toString(), "getPressedSpan", e)

        }
        return null
    }
}

代碼比較簡(jiǎn)單，就是對(duì)點(diǎn)擊區(qū)域判斷是否為鏈接，然后根據(jù)手勢(shì)的操作分別設(shè)置給ClickSpan是否按下，來改變鏈接的背景顏色。

另外需要注意一點(diǎn)的是必須要調(diào)用下邊的代碼：

movementMethod = MyLinkMovementMethod.instance

此方法設(shè)置鏈接的點(diǎn)擊。 另外，不同的機(jī)型上系統(tǒng)會(huì)有一個(gè)鏈接的高亮顏色，我們需要調(diào)用

highlightColor = Color.TRANSPARENT

來取消掉。

這樣，鏈接的顯示和點(diǎn)擊交互就完成了。 具體效果：

點(diǎn)擊獲取源碼

總結(jié)

原文鏈接：https://juejin.cn/post/7035606854575063053

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