textview.settext文本在android 10上有很多替代跨度

Question

在Android10手机上，当textview set text(spannable)有很多ReplacementSpans时，在view.onMeasure中需要花费大量的时间，所以发生了ANR。

我在三星G981N和G975N手机(安卓10)上进行了测试。

根据android profiler的数据，android.graphics.text.LineBreaker.nComputeLineBreaks运行了大部分的运行时间。

Here图像，并在我测试的代码下面。

(compileSdkVersion 29)

(使用ReplacementSpan将A*100替换为K*2 )

(textLength = 3000正常运行，但30000发生异常)

private fun test() {
    val text = StringBuffer()
    val textLength = 30000
    val spanLength = 100

    var count = 0
    while (count < textLength) {
        text.append("A")
        count++
    }

    val spannable = text.toSpannable()

    var index = 0
    while (index < (textLength / spanLength)) {
        val span = TestReplacementSpan()
        spannable.setSpan(span, index * spanLength, index * spanLength + spanLength, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE)
        index++
    }

    binding.textview.text = spannable
}

class TestReplacementSpan : ReplacementSpan() {
    private val replaceText = "KK"

    override fun getSize(paint: Paint, text: CharSequence, start: Int, end: Int, fm: FontMetricsInt?): Int {
        if (fm != null) {
            paint.getFontMetricsInt(fm)
        }
       return Math.round(paint.measureText(replaceText, 0, replaceText.length))
    }

    override fun draw(canvas: Canvas, text: CharSequence, start: Int, end: Int, x: Float, top: Int, y: Int, bottom: Int, paint: Paint) {
        canvas.drawText(replaceText, 0, replaceText.length, Math.max(x, 0f), y.toFloat(), paint)
    }
}

Answer 1

添加下面的代码，问题就解决了

textview.breakStrategy = Layout.BREAK_STRATEGY_SIMPLE