Android 如何自动调整微调器的大小下拉菜单

如何解决Android 如何自动调整微调器的大小下拉菜单

如何根据所选元素的 TextView 宽度自动调整 DropDownMenu 的大小。

As seen by the image below when the 'Short Text' is selected there is unwanted area,this is not a problem if we want to to adjust the start of the menu to another element,but if we want to adjust the end菜单到另一个元素，有一个不应该存在的差距。

所以我的问题是：有没有办法去除不需要的区域，或者至少将 TextView 和 ImageView 调整到右侧？（如下图所示）

以下是全部代码：

..layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <com.slaviboy.dropdown.DropDownMenu
        android:id="@+id/dropDownMenu1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:animationCache="true"
        android:background="#00ffff"
        android:dropDownWidth="wrap_content"
        android:spinnerMode="dropdown"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <com.slaviboy.dropdown.DropDownMenu
        android:id="@+id/dropDownMenu2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:animationCache="true"
        android:background="#00ffff"
        android:dropDownWidth="wrap_content"
        android:spinnerMode="dropdown"
        android:layout_marginTop="20dp"
        app:layout_constraintEnd_toEndOf="@id/dropDownMenu1"
        app:layout_constraintTop_toBottomOf="@id/dropDownMenu1" />

</androidx.constraintlayout.widget.ConstraintLayout>

..layout/drop_down_menu_item.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#ffff00">

    <TextView
        android:id="@+id/itemName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:background="#ff0000"
        android:ellipsize="end"
        android:gravity="start|center_vertical"
        android:maxLines="1"
        android:text="Hello World!"
        android:textColor="#5A5A5A"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/downArrowSymbol"
        app:layout_constraintHorizontal_chainStyle="packed"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/downArrowSymbol"
        android:layout_width="30dp"
        android:layout_height="0dp"
        android:adjustViewBounds="true"
        android:background="#00ff00"
        android:padding="4dp"
        android:scaleType="fitCenter"
        android:src="@drawable/ic_arrow"
        android:visibility="visible"
        app:layout_constraintBottom_toBottomOf="@id/itemName"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_chainStyle="packed"
        app:layout_constraintStart_toEndOf="@id/itemName"
        app:layout_constraintTop_toTopOf="@id/itemName" />

</androidx.constraintlayout.widget.ConstraintLayout>

..drawable/ic_arrow.xml

<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:width="451.847dp"
    android:height="451.847dp"
    android:viewportWidth="451.847"
    android:viewportHeight="451.847">
    <path
        android:fillColor="#5A5A5A"
        android:pathData="M225.923,354.706c-8.098,0 -16.195,-3.092 -22.369,-9.263L9.27,151.157c-12.359,-12.359 -12.359,-32.397 0,-44.751c12.354,-12.354 32.388,-12.354 44.748,0l171.905,171.915l171.906,-171.909c12.359,-12.354 32.391,-12.354 44.744,0c12.365,12.354 12.365,32.392 0,44.751L248.292,345.449C242.115,351.621 234.018,354.706 225.923,354.706z"/>
</vector>

DropDownAdapter.kt

import android.content.Context
import android.graphics.Color
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.AdapterView
import android.widget.ArrayAdapter
import android.widget.ImageView
import android.widget.TextView
import androidx.constraintlayout.widget.ConstraintLayout
import java.util.*

class DropDownAdapter(context: Context,var layoutSrc: Int,var nameList: ArrayList<String>) :
    ArrayAdapter<String>(context,nameList),AdapterView.OnItemSelectedListener {

    var selectedViewPosition = -1

    override fun getCount(): Int {
        return nameList.size
    }

    override fun getItem(position: Int): String {
        return nameList[position]
    }

    override fun getItemId(position: Int): Long {
        return position.toLong()
    }

    override fun getView(position: Int,convertView: View?,parent: ViewGroup): View {
        return initView(position,convertView,parent,true)
    }

    override fun getDropDownView(position: Int,parent)
    }

    override fun onNothingSelected(parent: AdapterView<*>) {
    }

    override fun onItemSelected(parent: AdapterView<*>,view: View,position: Int,id: Long) {
        selectedViewPosition = position
    }

    private fun initView(position: Int,parent: ViewGroup,fromItemSelection: Boolean = false): View {

        // inflate the layout if view does not exist
        val itemView = convertView ?: LayoutInflater.from(context).inflate(layoutSrc,false)

        // get child elements
        val itemName: TextView = itemView.findViewById(R.id.itemName)
        val dropArrowSymbol: ImageView = itemView.findViewById(R.id.downArrowSymbol)

        // get string name
        val currentItem: String = getItem(position)
        itemName.text = currentItem

        if (!fromItemSelection) {
            (itemName.layoutParams as ConstraintLayout.LayoutParams).endToStart = -1
            dropArrowSymbol.visibility = View.INVISIBLE
        } else {
            itemName.setTextColor(Color.DKGRAY)
            dropArrowSymbol.visibility = View.VISIBLE
            (itemName.layoutParams as ConstraintLayout.LayoutParams).setMargins(0,0)
        }

        return itemView
    }

}

下拉菜单.kt

import android.content.Context
import android.util.AttributeSet
import androidx.appcompat.widget.ListPopupWindow
import java.lang.Exception

open class DropDownMenu : androidx.appcompat.widget.AppCompatSpinner {

    constructor(context: Context) : super(context)
    constructor(context: Context,attrs: AttributeSet?) : super(context,attrs)
    constructor(context: Context,attrs: AttributeSet?,defStyleAttr: Int) : super(context,attrs,defStyleAttr)

    init {

        try {

            // get private property and make it accessible
            val popup = androidx.appcompat.widget.AppCompatSpinner::class.java.getDeclaredField("mPopup")
            popup.isAccessible = true

            // get the popup window
            val popupWindow = popup.get(this) as ListPopupWindow
            popupWindow.isModal = false

        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

}

Android 如何自动调整微调器的大小下拉菜单

如何解决Android 如何自动调整微调器的大小下拉菜单

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