ScrollView内嵌TextView插入新文本后无法居中问题如何解决？

• 居中属性被覆盖：代码中先设置了resultdop.textAlignment = View.TEXT_ALIGNMENT_CENTER，紧接着又赋值为View.TEXT_ALIGNMENT_GRAVITY，前面的居中设置直接被覆盖失效。
• UI操作位置错误：给resultdop设置居中属性的代码写在doAsync异步块外面，而异步请求是耗时操作，属性设置先执行，后续在子线程更新resultdop文本时，部分设备上会导致原本的居中属性被重置，且在子线程直接操作TextView更新UI本身就不符合安卓开发规范，是属性不生效的核心原因。
• 冗余属性冲突：同时给ScrollView、LinearLayout、TextView都设置了textAlignment，多层属性叠加会产生冲突。

1. 修正业务代码逻辑，将所有UI操作切换到主线程执行，删除重复覆盖的错误赋值，修改后代码如下：

if (resultdop.text == ""){
    val city: String = userfield.text.toString()
    val key = "e9c95bab1d070877909fd3e55310c60c"
    val url = "https://api.openweathermap.org/data/2.5/weather?q=$city&appid=$key&units=metric&lang=ru"
    val urls = "https://api.openweathermap.org/data/2.5/forecast?q=$city&appid=$key&units=metric&lang=ru"
    doAsync {
        val apiresponse = URL(url).readText()
        val weather = JSONObject(apiresponse).getJSONArray("weather")
        val desc = weather.getJSONObject(0).getString("description")
        val main = JSONObject(apiresponse).getJSONObject("main")
        val temp = main.getString("temp")
        val apiresponses = URL(urls).readText()
        val list = JSONObject(apiresponses).getJSONArray("list")
        var otvet = ""
        for (i in 1 until list.length()){
            val obj = list.getJSONObject(i)
            val tempd = obj.getJSONObject("main").getInt("temp")
            val weatherd = obj.getJSONArray("weather")
            val descd = weatherd.getJSONObject(0).getString("description")
            val time = obj.getString("dt_txt")
            otvet += "$time \n $tempd ℃, $descd \n \n"
        }
        // 所有UI操作切到主线程执行
        uiThread {
            resultfield.text = "Температура: $temp ℃, $desc"
            resultdop.text = otvet
            // 只保留必要的居中设置，不要重复覆盖
            resultdop.gravity = Gravity.CENTER_HORIZONTAL
            resultdop.textAlignment = View.TEXT_ALIGNMENT_CENTER
        }
    }
}

2. 优化XML布局，删除父布局冗余的textAlignment属性，避免层级冲突：

<ScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_below="@id/result">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <TextView
            android:id="@+id/resultdop"
            android:textSize="20sp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:fontFamily="sans-serif-light"
            android:gravity="center_horizontal"
            android:textAlignment="center"
            android:textColor="@color/white" />
    </LinearLayout>
</ScrollView>

内容的提问来源于stack exchange，提问作者Roych_Sanderson