右边的字母操作行可以自定义一个组件继承AppCompatTextView，为什么要用它呢，而不用TextView呢？因为UI设计限定了一个文本的宽度，但是文本的长度可能比较长，如果设定一个固定的textSize，就导致一部分文本无法显示，而AppCompatTextView最显著的特点是可以自适应字体宽度大小变化。这个特点很有用，可以让文本随着文本宽度的变化，限定在一个固定范围内完整显示出来：

修改微信通信录界面的fragment布局
contactlist_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.wxchatdemo.MainWeixin">
    <ListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:divider="@drawable/main_list_divider_line"
        android:dividerHeight="1.5px"
        android:layout_marginBottom="50dp" />
    <com.example.wxchatdemo.tools.SideBar
        android:id="@+id/side_bar"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentRight="true"
        android:layout_marginBottom="100dp"
        android:layout_marginTop="100dp"
        android:paddingRight="10dp"
        android:textColor="@color/black"
        android:textSize="9sp" />
</RelativeLayout>

fragment整体布局使用相对布局，这样可以通过 android:layout_alignParentRight="true"属性指定右边的自定义字母导航（SideBar继承AppCompatTextView）在父容器右边（即在屏幕中间的右边），相对布局包括两个组件（ListView,SideBar)

创建自定义组件SideBar.java继承AppCompatTextView
SideBar.java

package com.example.wxchatdemo;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;

public class SideBar extends android.support.v7.widget.AppCompatTextView {
    private String[] letters = new String[]{"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", "#"};
    private Paint textPaint;
    private Paint bigTextPaint;
    private Paint scaleTextPaint;
    private Canvas canvas;
    private int itemH;
    private int w;
    private int h;
    /**
     * 普通情况下字体大小
     */
    float singleTextH;
    /**
     * 缩放离原始的宽度
     */
    private float scaleWidth;
    /**
     * 滑动的Y
     */
    private float eventY = 0;
    /**
     * 缩放的倍数
     */
    private int scaleSize = 1;
    /**
     * 缩放个数item，即开口大小
     */
    private int scaleItemCount = 6;
    private ISideBarSelectCallBack callBack;

    public SideBar(Context context) {
        this(context, null);
    }

    public SideBar(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public SideBar(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(attrs);
    }

    private void init(AttributeSet attrs) {
        if (attrs != null) {
            TypedArray ta = getContext().obtainStyledAttributes(attrs, R.styleable.SideBar);
            scaleSize = ta.getInteger(R.styleable.SideBar_scaleSize, 1);
            scaleItemCount = ta.getInteger(R.styleable.SideBar_scaleItemCount, 6);
            scaleWidth = ta.getDimensionPixelSize(R.styleable.SideBar_scaleWidth, dp(100));
            ta.recycle();
        }
        textPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        textPaint.setColor(getCurrentTextColor());
        textPaint.setTextSize(getTextSize());
        textPaint.setTextAlign(Paint.Align.CENTER);
        bigTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        bigTextPaint.setColor(getCurrentTextColor());
        bigTextPaint.setTextSize(getTextSize() * (scaleSize + 3));
        bigTextPaint.setTextAlign(Paint.Align.CENTER);
        scaleTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        scaleTextPaint.setColor(getCurrentTextColor());
        scaleTextPaint.setTextSize(getTextSize() * (scaleSize + 1));
        scaleTextPaint.setTextAlign(Paint.Align.CENTER);
    }

    public void setDataResource(String[] data) {
        letters = data;
        invalidate();
    }

    public void setOnStrSelectCallBack(ISideBarSelectCallBack callBack) {
        this.callBack = callBack;
    }

    /**
     * 设置字体缩放比例     *     * @param scale
     */
    public void setScaleSize(int scale) {
        scaleSize = scale;
        invalidate();
    }

    /**
     * 设置缩放字体的个数，即开口大小     *     * @param scaleItemCount
     */
    public void setScaleItemCount(int scaleItemCount) {
        this.scaleItemCount = scaleItemCount;
        invalidate();
    }

    private int dp(int px) {
        final float scale = getContext().getResources().getDisplayMetrics().density;
        return (int) (px * scale + 0.5f);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
            case MotionEvent.ACTION_MOVE:
                if (event.getX() > (w - getPaddingRight() - singleTextH - 10)) {
                    eventY = event.getY();
                    invalidate();
                    return true;
                } else {
                    eventY = 0;
                    invalidate();
                    break;
                }
            case MotionEvent.ACTION_CANCEL:
                eventY = 0;
                invalidate();
                return true;
            case MotionEvent.ACTION_UP:
                if (event.getX() > (w - getPaddingRight() - singleTextH - 10)) {
                    eventY = 0;
                    invalidate();
                    return true;
                } else
                    break;
        }
        return super.onTouchEvent(event);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        this.canvas = canvas;
        DrawView(eventY);
    }

    private void DrawView(float y) {
        int currentSelectIndex = -1;
        if (y != 0) {
            for (int i = 0; i < letters.length; i++) {
                float currentItemY = itemH * i;
                float nextItemY = itemH * (i + 1);
                if (y >= currentItemY && y < nextItemY) {
                    currentSelectIndex = i;
                    if (callBack != null) {
                        callBack.onSelectStr(currentSelectIndex, letters[i]);
                    }                    //画大的字母
                    Paint.FontMetrics fontMetrics = bigTextPaint.getFontMetrics();
                    float bigTextSize = fontMetrics.descent - fontMetrics.ascent;
                    canvas.drawText(letters[i], w - getPaddingRight() - scaleWidth - bigTextSize,
                            singleTextH + itemH * i, bigTextPaint);
                }
            }
        }
        drawLetters(y, currentSelectIndex);
    }

    private void drawLetters(float y, int index) {        //第一次进来没有缩放情况，默认画原图
        if (index == -1) {
            w = getMeasuredWidth();
            h = getMeasuredHeight();
            itemH = h / letters.length;
            Paint.FontMetrics fontMetrics = textPaint.getFontMetrics();
            singleTextH = fontMetrics.descent - fontMetrics.ascent;
            for (int i = 0; i < letters.length; i++) {
                canvas.drawText(letters[i], w - getPaddingRight(), singleTextH + itemH * i, textPaint);
            }            //触摸的时候画缩放图
        } else {            //遍历所有字母
            for (int i = 0; i < letters.length; i++) {                //要画的字母的起始Y坐标
                float currentItemToDrawY = singleTextH + itemH * i;
                float centerItemToDrawY;
                if (index < i)
                    centerItemToDrawY = singleTextH + itemH * (index + scaleItemCount);
                else
                    centerItemToDrawY = singleTextH + itemH * (index - scaleItemCount);
                float delta = 1 - Math.abs((y - currentItemToDrawY) / (centerItemToDrawY - currentItemToDrawY));
                float maxRightX = w - getPaddingRight();                //如果大于0，表明在y坐标上方
                scaleTextPaint.setTextSize(getTextSize() + getTextSize() * delta);
                float drawX = maxRightX - scaleWidth * delta;                //超出边界直接花在边界上
                if (drawX > maxRightX)
                    canvas.drawText(letters[i], maxRightX, singleTextH + itemH * i, textPaint);
                else
                    canvas.drawText(letters[i], drawX, singleTextH + itemH * i, scaleTextPaint);
            }
        }
    }

    public interface ISideBarSelectCallBack {
        void onSelectStr(int index, String selectStr);
    }
}

右侧字母导航条，包括3个自定义的属性，下面将给出

在colors.xml文件添加如下代码
colors.xml

    <declare-styleable name="SideBar">
        <attr name="scaleSize" format="integer"/>
        <attr name="scaleItemCount" format="integer"/>
        <attr name="scaleWidth" format="dimension"/>
    </declare-styleable>

要在字母导航中点击每一个字母可跳转相应分组，需要借助汉字转拼音工具类和自定义字母排序类，我们知道，java中是没有提供接口和方法让我们直接将汉字转成拼音的。在此我选择了使用第三方jar包的方式，因为它体积不大而且更加准确。

创建汉字转拼音工具类Cn2Spell.java
Cn2Spell.java

package com.example.wxchatdemo.tools;

import net.sourceforge.pinyin4j.PinyinHelper;
import net.sourceforge.pinyin4j.format.HanyuPinyinCaseType;
import net.sourceforge.pinyin4j.format.HanyuPinyinOutputFormat;
import net.sourceforge.pinyin4j.format.HanyuPinyinToneType;

/** * 汉字转换位汉语拼音，英文字符不变 */
public class Cn2Spell {
    public static StringBuffer sb = new StringBuffer();
    /**     * 获取汉字字符串的首字母，英文字符不变     * 例如：阿飞→af     */
    public static String getPinYinHeadChar(String chines) {
        sb.setLength(0);
        char[] chars = chines.toCharArray();
        HanyuPinyinOutputFormat defaultFormat = new HanyuPinyinOutputFormat();
        defaultFormat.setCaseType(HanyuPinyinCaseType.LOWERCASE);
        defaultFormat.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
        for (int i = 0; i < chars.length; i++) {
            if (chars[i] > 128) {
                try {
                    sb.append(PinyinHelper.toHanyuPinyinStringArray(chars[i], defaultFormat)[0].charAt(0));                }
                catch (Exception e) {
                    e.printStackTrace();                }
            }
            else {
                sb.append(chars[i]);            }
        }
        return sb.toString();    }
        /**     * 获取汉字字符串的第一个字母     */
        public static String getPinYinFirstLetter(String str) {
            sb.setLength(0);
            char c = str.charAt(0);
            String[] pinyinArray = PinyinHelper.toHanyuPinyinStringArray(c);
            if (pinyinArray != null) {
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