JTCharIndexView

dependencies {
    ......
    implementation 'com.william:JTCharIndexView:1.0.0'
}

非常简单，懒得说明了，详见demo
package com.william.charindexviewdemo

import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.widget.Toast
import com.william.charindexview.CharIndexView
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() ,CharIndexView.OnCharIndexChangedListener{

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val labels = charArrayOf('#','A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K',
            'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z')

        this.civ.setCHARS(labels)
        this.civ.requestLayout()

        this.civ.setOnCharIndexChangedListener(this)
        this.civ.invalidate()
    }


    override fun onCharIndexSelected(currentIndex: String?) {
        Toast.makeText(this,"点击了"+currentIndex,Toast.LENGTH_SHORT).show()
    }
}

Copyright 2018 william Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.