如果文本字符串小于屏幕大小，则使 textview 选取框

Posted 2023-04-19

【中文标题】如果文本字符串小于屏幕大小，则使 textview 选取框

【英文标题】：Make textview marquee if text string is smaller than screen size

【发布时间】：2021-08-14 18:24:47

【问题描述】：

当 textview 文本为“小”时，textview 不会滚动，但当 textview 文本“较大且文本超出屏幕大小”时，它会滚动。 我也不希望我的文字在“小”时选框

XML 文本视图：

<TextView
                    android:id="@+id/tickler_message"
                    style="@style/AppTheme.MarqueeTextStyle"
                    android:layout_
                    android:layout_
                    tools:text="@string/placeholder_marquee_text"
                    android:ellipsize="marquee"
                    android:focusable="true"
                    android:focusableInTouchMode="true"
                    android:singleLine="true"
                    android:scrollHorizontally="true"
                    android:marqueeRepeatLimit="marquee_forever"/>

活动：

binding.ticklerMessage.text = ticklerPlainText
binding.ticklerMessage.isSelected = true

【参考方案1】：

我们需要用文本检查textview的宽度，

If it exceed screen width -> textview marquee text properties, 
else -> animate textview from left to right.

创建动画tickler_translation.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">

    <translate
        android:duration="10000"
        android:fromXDelta="100%"
        android:fillEnabled = "true"
        android:repeatCount="infinite"
        android:repeatMode="restart"
        android:toXDelta="0%" />

</set>

文本视图

<TextView
                    android:id="@+id/tickler_message"
                    style="@style/AppTheme.MarqueeTextStyle"
                    android:layout_
                    android:layout_
                    tools:text="@string/placeholder_marquee_text"
                    android:ellipsize="marquee"
                    android:focusable="true"
                    android:singleLine="true"
                    android:focusableInTouchMode="true"
                    android:scrollHorizontally="true"
                    android:marqueeRepeatLimit="marquee_forever"/>

活动中

if (textCanScroll(ticklerMessage, ticklerPlainText)) 
    //Show Marquee text if text length is greater than screen width
    ticklerMessage.text = ticklerPlainText
    ticklerMessage.maxLength(ticklerPlainText.length)
    ticklerMessage.isSelected = true
    ticklerMessage.gravity = Gravity.CENTER
    ticklerLayout.makeVisible()
 else 
    //Animate text horizontally if length is lesser than screen width
    val animation = AnimationUtils.loadAnimation(it, R.anim.tickler_translation)
    ticklerMessage.startAnimation(animation)
    ticklerMessage.text = ticklerPlainText
    ticklerMessage.gravity = Gravity.START or Gravity.CENTER_VERTICAL
    ticklerLayout.makeVisible()


private fun textCanScroll(textView: TextView, text: String): Boolean 
        try 
            val bounds = Rect()
            val textPaint: Paint = textView.paint
            textPaint.getTextBounds(text, 0, text.length, bounds)
            val height: Int = bounds.height()
            val width: Int = bounds.width()
            if (activity != null) 
                val screenWidth = Resources.getSystem().displayMetrics.widthPixels
                return width >= screenWidth
            
         catch (exception: Exception) 
            return false
        
        return false