Android字母索引、Android通讯录索引、Android地区索引、Android索引

本文介绍了Android中字母索引、通讯录索引和地区索引的实现，为Android应用的索引功能提供指南。

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import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;


import java.util.LinkedList;



public class AlphabeticalView extends View {
   
   

    private Paint mPaint;
    private Paint mPaint3;
    private String currentLetter = "";
    private int mHeight, mWidth;
    private onTouchSelectListener mListener;

    private Rect rect = new Rect();
    private int r = DisplayUtil.dpToPx(10);
    // 单个item 宽高
    private int w = DisplayUtil.dpToPx(20);
    private int h = r * 2 + DisplayUtil.dpToPx(2) * 2;
    // 26个字母
    // public String[] letters = {"A", "B", "C", "D", "E", "F", "G"};

    private LinkedList<String> letters;

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

    public AlphabeticalView(Context context, @Nullable AttributeSet attrs) {
   
   
        this(context, attrs, 0);
    }

    public AlphabeticalView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
   
   
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
   
   
        mPaint = new Paint();
        mPaint.setAntiAlias(true);//抗锯齿
        mPaint.setTextSize(DisplayUtil.spToPx(14));//文字 sp转px
        mPaint.setColor(Color.BLACK