1. 默认样式

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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">
    <me.luzhuo.indexbarviewdemo.IndexBarView
        android:id="@+id/indexBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:index_text_space="5dp"
        android:padding="5dp"
        android:layout_alignParentRight="true"/>
    <TextView
        android:id="@+id/index_tip"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:layout_centerInParent="true"
        android:background="@drawable/bg_index_tip"
        android:gravity="center"
        android:textColor="@android:color/white"
        android:textSize="48sp"
        android:visibility="gone"
        tools:text="A"
        tools:visibility="visible" />
</RelativeLayout>

IndexBarView indexBar = findViewById(R.id.indexBar);
TextView indexBarTip = findViewById(R.id.index_tip);
indexBar.setOnIndexBarCallback(new IndexBarView.OnIndexBarCallback() {
    @Override
    public void onPressing(int index, String indexStr) {
        Log.e(TAG, "index: " + index + " indexStr: " + indexStr);
        indexBarTip.setVisibility(View.VISIBLE);
        indexBarTip.setText(indexStr);
    }
    @Override
    public void onPressed() {
        Log.e(TAG, "onPressed");
        indexBarTip.setVisibility(View.GONE);
    }
});

2. 使用样式

内置样式 CircleBackgroundStyle

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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">
    <me.luzhuo.indexbarviewdemo.IndexBarView
        android:id="@+id/indexBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:index_text_size_normal="14sp"
        app:index_text_size_pressed="14sp"
        app:index_text_color_pressed="#ffffff"
        app:index_text_color_normal="#333333"
        app:index_text_space="5dp"
        android:padding="5dp"
        android:layout_alignParentRight="true"/>
    <TextView
        android:id="@+id/index_tip"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:layout_centerInParent="true"
        android:background="@drawable/bg_index_tip"
        android:gravity="center"
        android:textColor="@android:color/white"
        android:textSize="48sp"
        android:visibility="gone"
        tools:text="A"
        tools:visibility="visible" />
</RelativeLayout>

IndexBarView indexBar = findViewById(R.id.indexBar);
TextView indexBarTip = findViewById(R.id.index_tip);
indexBar.setPressedStyle(new CircleBackgroundStyle(indexBar.getPressedTextSize(), indexBar.getPressedTextColor(), 0xFF3700B3));
indexBar.setOnIndexBarCallback(new IndexBarView.OnIndexBarCallback() {
    @Override
    public void onPressing(int index, String indexStr) {
        Log.e(TAG, "index: " + index + " indexStr: " + indexStr);
        indexBarTip.setVisibility(View.VISIBLE);
        indexBarTip.setText(indexStr);
    }
    @Override
    public void onPressed() {
        Log.e(TAG, "onPressed");
        indexBarTip.setVisibility(View.GONE);
    }
});

3. 自定义数据

indexBar.setIndexStrings(new String[]{"顶部", "A", "B", "C", "中", "国", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "#"});