仿IOS 带字母索引的滑轮控件
【摘要】
效果大概就是这样,右边是字母索引效果
做开发的时候，经常碰到产品经理设计出来的界面是参考IOS控件设计出来的 ，比如上图效果 ios有个控件是UIPickerView 就是可以上下滑动 并有些3d效果，非常炫。
但是android并没有提供这样的原生控件支持，所以需要通过其...
效果大概就是这样,右边是字母索引效果
做开发的时候，经常碰到产品经理设计出来的界面是参考IOS控件设计出来的 ，比如上图效果 ios有个控件是UIPickerView 就是可以上下滑动 并有些3d效果，非常炫。
但是android并没有提供这样的原生控件支持，所以需要通过其他方式实现类似效果。上图就是我开发中用到的一个效果。
话不多说 ，直接上代码：
Activity
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package com.example.picscrollview;
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import java.util.ArrayList;
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import java.util.Collections;
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import java.util.List;
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import com.example.picscrollview.PickerScrollView.onSelectListener;
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import com.example.test.R;
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import android.app.Activity;
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import android.os.Bundle;
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import android.view.View;
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import android.view.View.OnClickListener;
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import android.widget.Toast;
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public class MainActivity extends Activity implements OnClickListener {
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Boolean state_pressed = true;
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private String cities[] ={"北京版", "天津版", "上海版", "重庆版", "河北版", "山西版", "辽宁版", "吉林版", "黑龙江版", "江苏版", "浙江版", "安徽版",
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"福建版", "江西版", "山东版", "河南版", "湖北版", "湖南版", "广东版", "甘肃版", "四川版", "贵州版", "海南版", "云南版",
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"青海版", "陕西版", "广西版", "西藏版", "宁夏版", "新疆版", "内蒙古版", "澳门版", "香港版", "台湾版","全国版"};
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private String[] id = { "1", "2", "3", "4", "5", "6" ,"7","8","9","10","11","12","13","14","15","16",
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"17", "18", "19", "20", "21", "22" ,"23","24","25","26","27","28","29","30","31","32","33","34","35"};
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private PickerScrollView pickerscrlllview; // 滚动选择器
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private List<Pickers> list; // 滚动选择器数据
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private CharacterParser mCharacterParser;
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@Override
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protected void onCreate(Bundle savedInstanceState) {
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super.onCreate(savedInstanceState);
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setContentView(R.layout.activity_main);
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initView();
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initData();
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}
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public void initView() {
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LetterSideBar letterSideBar = (LetterSideBar) findViewById(R.id.cs_letter_sb);
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letterSideBar
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.setOnTouchingLetterChangedListener(new LetterSideBar.OnTouchingLetterChangedListener() {
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@Override
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public void onTouchingLetterChanged(String letter) {
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int jumpPos = getPositionForSection(letter.charAt(0));
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pickerscrlllview.setSelected(jumpPos);
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}
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});
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pickerscrlllview = (PickerScrollView) findViewById(R.id.pickerscrlllview);
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pickerscrlllview.setOnSelectListener(pickerListener);
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findViewById(R.id.location_confirm_btn).setOnClickListener(this);
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}
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private void initData() {
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mCharacterParser = CharacterParser.getInstance();
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list = filledData();
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PinyinComparator pinyinComparator = new PinyinComparator();
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Collections.sort(list, pinyinComparator);
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pickerscrlllview.setData(list);
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pickerscrlllview.setSelected(0);
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}
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@Override
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protected void onResume() {
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super.onResume();
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}
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public void onPause() {
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super.onPause();
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}
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private List<Pickers> filledData() {
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List<Pickers> sortList = new ArrayList<Pickers>();
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for (int i = 0, n = cities.length; i < n; i++) {
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Pickers picker = new Pickers();
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picker.setShowConetnt(cities[i]);
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picker.setShowId(id[i]);
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String pinyin = mCharacterParser.getSelling(cities[i]);
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picker.setPinyin(pinyin);
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String sortString = pinyin.substring(0, 1).toUpperCase();
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if (sortString.matches("[A-Z]")) {
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picker.setSortLetter(sortString.toUpperCase());
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} else {
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picker.setSortLetter("#");
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}
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sortList.add(picker);
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}
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return sortList;
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}
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public int getPositionForSection(int section) {
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for (int i = 0; i < list.size(); i++) {
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String sortStr = list.get(i).getSortLetter();
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char firstChar = sortStr.toUpperCase().charAt(0);
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if (firstChar == section) {
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return i;
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}
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}
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return -1;
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}
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onSelectListener pickerListener = new onSelectListener() {
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@Override
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public void onSelect(Pickers pickers) {
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Toast.makeText(MainActivity.this, pickers.getShowConetnt(), Toast.LENGTH_LONG).show();
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}
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};
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@Override
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public void onBackPressed() {
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super.onBackPressed();
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}
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@Override
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public void onClick(View v) {
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switch (v.getId()) {
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default:
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break;
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}
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}
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}
自定义滑动view
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package com.example.picscrollview;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.Timer;
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import java.util.TimerTask;
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import com.example.test.R;
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import android.annotation.SuppressLint;
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import android.content.Context;
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import android.graphics.Canvas;
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import android.graphics.Paint;
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import android.graphics.Paint.Align;
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import android.graphics.Paint.FontMetricsInt;
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import android.graphics.Paint.Style;
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import android.os.Handler;
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import android.os.Message;
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import android.util.AttributeSet;
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import android.view.MotionEvent;
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import android.view.View;
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/**
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* 自定义滚动选择器
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*
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* @author zlw
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*
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*/
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@SuppressLint({ "HandlerLeak", "ClickableViewAccessibility" })
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public class PickerScrollView extends View {
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public static final String TAG = "PickerView";
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/**
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* text之间间距和minTextSize之比
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*/
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public static final float MARGIN_ALPHA = 2.8f;
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/**
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* 自动回滚到中间的速度
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*/
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public static final float SPEED = 2;
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private List<Pickers> mDataList;
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/**
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* 选中的位置，这个位置是mDataList的中心位置，一直不变
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*/
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private int mCurrentSelected;
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private Paint mPaint;
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private float mMaxTextSize = 14;
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private float mMinTextSize = 6;
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private float mMaxTextAlpha = 255;
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private float mMinTextAlpha = 120;
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private int mColorText = 0x333333;
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private int mViewHeight;
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private int mViewWidth;
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private float mLastDownY;
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/**
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* 滑动的距离
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*/
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private float mMoveLen = 0;
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private boolean isInit = false;
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private onSelectListener mSelectListener;
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private Timer timer;
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private MyTimerTask mTask;
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Handler updateHandler = new Handler() {
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@Override
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public void handleMessage(Message msg) {
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if (Math.abs(mMoveLen) < SPEED) {
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mMoveLen = 0;
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if (mTask != null) {
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mTask.cancel();
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mTask = null;
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performSelect();
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}
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} else
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// 这里mMoveLen / Math.abs(mMoveLen)是为了保有mMoveLen的正负号，以实现上滚或下滚
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mMoveLen = mMoveLen - mMoveLen / Math.abs(mMoveLen) * SPEED;
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invalidate();
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}
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};
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public PickerScrollView(Context context) {
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super(context);
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init();
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}
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public PickerScrollView(Context context, AttributeSet attrs) {
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super(context, attrs);
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init();
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}
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public void setOnSelectListener(onSelectListener listener) {
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mSelectListener = listener;
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}
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private void performSelect() {
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if (mSelectListener != null)
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mSelectListener.onSelect(mDataList.get(mCurrentSelected));
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}
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public void setData(List<Pickers> datas) {
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mDataList = datas;
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mCurrentSelected = datas.size() / 2;
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invalidate();
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}
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/**
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* 选择选中的item的index
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*
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* @param selected
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*/
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public void setSelected(int selected) {
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mCurrentSelected = selected;
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int distance = mDataList.size() / 2 - mCurrentSelected;
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if (distance < 0)
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for (int i = 0; i < -distance; i++) {
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moveHeadToTail();
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mCurrentSelected--;
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}
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else if (distance > 0)
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for (int i = 0; i < distance; i++) {
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moveTailToHead();
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mCurrentSelected++;
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}
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invalidate();
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}
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/**
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* 选择选中的内容
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*
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* @param mSelectItem
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*/
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public void setSelected(String mSelectItem) {
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for (int i = 0; i < mDataList.size(); i++)
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if (mDataList.get(i).equals(mSelectItem)) {
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setSelected(i);
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break;
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}
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}
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private void moveHeadToTail() {
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Pickers head = mDataList.get(0);
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mDataList.remove(0);
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mDataList.add(head);
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}
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private void moveTailToHead() {
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Pickers tail = mDataList.get(mDataList.size() - 1);
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mDataList.remove(mDataList.size() - 1);
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mDataList.add(0, tail);
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}
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@Override
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protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
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super.onMeasure(widthMeasureSpec, heightMeasureSpec);
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mViewHeight = getMeasuredHeight();
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mViewWidth = getMeasuredWidth();
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// 按照View的高度计算字体大小
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mMaxTextSize = mViewHeight / 8.0f;
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mMinTextSize = mMaxTextSize / 2f;
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isInit = true;
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invalidate();
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}
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private void init() {
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timer = new Timer();
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mDataList = new ArrayList<Pickers>();
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mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
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mPaint.setStyle(Style.FILL);
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mPaint.setTextAlign(Align.CENTER);
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mPaint.setColor(getResources().getColor(R.color.white));
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}
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@Override
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protected void onDraw(Canvas canvas) {
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super.onDraw(canvas);
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// 根据index绘制view
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if (isInit)
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drawData(canvas);
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}
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private void drawData(Canvas canvas) {
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// 先绘制选中的text再往上往下绘制其余的text
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float scale = parabola(mViewHeight / 4.0f, mMoveLen);
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float size = (mMaxTextSize - mMinTextSize) * scale + mMinTextSize;
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mPaint.setTextSize(size);
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mPaint.setAlpha((int) ((mMaxTextAlpha - mMinTextAlpha) * scale + mMinTextAlpha));
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// text居中绘制，注意baseline的计算才能达到居中，y值是text中心坐标
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float x = (float) (mViewWidth / 2.0);
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float y = (float) (mViewHeight / 2.0 + mMoveLen);
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FontMetricsInt fmi = mPaint.getFontMetricsInt();
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float baseline = (float) (y - (fmi.bottom / 2.0 + fmi.top / 2.0));
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int indexs = mCurrentSelected;
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String textData = mDataList.get(indexs).getShowConetnt();
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canvas.drawText(textData, x, baseline, mPaint);
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// 绘制上方data
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for (int i = 1; (mCurrentSelected - i) >= 0; i++) {
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drawOtherText(canvas, i, -1);
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}
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// 绘制下方data
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for (int i = 1; (mCurrentSelected + i) < mDataList.size(); i++) {
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drawOtherText(canvas, i, 1);
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}
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}
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/**
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* @param canvas
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* @param position
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* 距离mCurrentSelected的差值
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* @param type
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* 1表示向下绘制，-1表示向上绘制
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*/
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private void drawOtherText(Canvas canvas, int position, int type) {
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float d = (float) (MARGIN_ALPHA * mMinTextSize * position + type
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* mMoveLen);
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float scale = parabola(mViewHeight / 4.0f, d);
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float size = (mMaxTextSize - mMinTextSize) * scale + mMinTextSize;
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mPaint.setTextSize(size);
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mPaint.setAlpha((int) ((mMaxTextAlpha - mMinTextAlpha) * scale + mMinTextAlpha));
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float y = (float) (mViewHeight / 2.0 + type * d);
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FontMetricsInt fmi = mPaint.getFontMetricsInt();
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float baseline = (float) (y - (fmi.bottom / 2.0 + fmi.top / 2.0));
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int indexs = mCurrentSelected + type * position;
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String textData = mDataList.get(indexs).getShowConetnt();
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canvas.drawText(textData, (float) (mViewWidth / 2.0), baseline, mPaint);
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}
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/**
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* 抛物线
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*
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* @param zero
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* 零点坐标
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* @param x
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* 偏移量
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* @return scale
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*/
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private float parabola(float zero, float x) {
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float f = (float) (1 - Math.pow(x / zero, 2));
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return f < 0 ? 0 : f;
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}
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@Override
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public boolean onTouchEvent(MotionEvent event) {
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switch (event.getActionMasked()) {
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case MotionEvent.ACTION_DOWN:
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doDown(event);
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break;
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case MotionEvent.ACTION_MOVE:
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doMove(event);
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break;
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case MotionEvent.ACTION_UP:
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doUp(event);
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break;
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}
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return true;
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}
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private void doDown(MotionEvent event) {
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if (mTask != null) {
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mTask.cancel();
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mTask = null;
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}
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mLastDownY = event.getY();
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}
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private void doMove(MotionEvent event) {
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mMoveLen += (event.getY() - mLastDownY);
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if (mMoveLen > MARGIN_ALPHA * mMinTextSize / 2) {
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// 往下滑超过离开距离
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moveTailToHead();
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mMoveLen = mMoveLen - MARGIN_ALPHA * mMinTextSize;
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} else if (mMoveLen < -MARGIN_ALPHA * mMinTextSize / 2) {
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// 往上滑超过离开距离
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moveHeadToTail();
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mMoveLen = mMoveLen + MARGIN_ALPHA * mMinTextSize;
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}
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mLastDownY = event.getY();
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invalidate();
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}
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private void doUp(MotionEvent event) {
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// 抬起手后mCurrentSelected的位置由当前位置move到中间选中位置
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if (Math.abs(mMoveLen) < 0.0001) {
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mMoveLen = 0;
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return;
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}
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if (mTask != null) {
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mTask.cancel();
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mTask = null;
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}
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mTask = new MyTimerTask(updateHandler);
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timer.schedule(mTask, 0, 10);
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}
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class MyTimerTask extends TimerTask {
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Handler handler;
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public MyTimerTask(Handler handler) {
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this.handler = handler;
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}
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@Override
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public void run() {
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handler.sendMessage(handler.obtainMessage());
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}
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}
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public interface onSelectListener {
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void onSelect(Pickers pickers);
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}
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}
核心的就是上面这个类。另外右边是个字母索引条。想必大家都做过，就不一一粘贴代码了。我将这个整理出来一个demo。
大家也可以加我的qq群讨论：Android开发经验交流群 454430053。DEMO源码下载
文章来源: wukong.blog.csdn.net，作者：再见孙悟空_，版权归原作者所有，如需转载，请联系作者。
原文链接：wukong.blog.csdn.net/article/details/51720554
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