Android自定义可循环的滚动选择器CycleWheelView

最近碰到个项目要使用到滚动选择器，原生的NumberPicker可定制性太差，不大符合UI要求。
网上开源的WheelView是用ScrollView写的，不能循环滚动，而且当数据量很大时要加载的Item太多，性能非常低。
然后，还是自己写一个比较靠谱，用的是ListView实现的。写完自己体验了一下，性能不错，再大的数据也不怕了。
感觉不错，重新封装了一下，提供了一些接口可以直接按照自己的需求定制，调用方法在MainActivity中。
补个图片： 

不多说了，直接上代码：

CycleWheelView.java:

package com.example.wheelviewdemo;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;

public class CycleWheelView extends ListView {
 public static final String TAG = CycleWheelView.class.getSimpleName();
 private static final int COLOR_DIVIDER_DEFALUT = Color.parseColor("#747474");
 private static final int HEIGHT_DIVIDER_DEFAULT = 2;
 private static final int COLOR_SOLID_DEFAULT = Color.parseColor("#3e4043");
 private static final int COLOR_SOLID_SELET_DEFAULT = Color.parseColor("#323335");
 private static final int WHEEL_SIZE_DEFAULT = 3;
 private Handler mHandler;
 private CycleWheelViewAdapter mAdapter;
 
 private List<String> mLabels;
 
 private int mLabelSelectColor = Color.WHITE;
 
 private int mLabelColor = Color.GRAY;
 
 private float mAlphaGradual = 0.7f;
 
 private int dividerColor = COLOR_DIVIDER_DEFALUT;
 
 private int dividerHeight = HEIGHT_DIVIDER_DEFAULT;
 
 private int seletedSolidColor = COLOR_SOLID_SELET_DEFAULT;
 
 private int solidColor = COLOR_SOLID_DEFAULT;
 
 private int mWheelSize = WHEEL_SIZE_DEFAULT;
 
 private int mItemLayoutId;
 
 private int mItemLabelTvId;
 
 private int mItemHeight;
 private boolean cylceEnable;
 private int mCurrentPositon;
 private WheelItemSelectedListener mItemSelectedListener;
 public CycleWheelView(Context context, AttributeSet attrs, int defStyle) {
  super(context, attrs, defStyle);
 }
 public CycleWheelView(Context context, AttributeSet attrs) {
  super(context, attrs);
  init();
 }
 public CycleWheelView(Context context) {
  super(context);
 }
 private void init() {
  mHandler = new Handler();
  mItemLayoutId = R.layout.item_cyclewheel;
  mItemLabelTvId = R.id.tv_label_item_wheel;
  mAdapter = new CycleWheelViewAdapter();
  setVerticalScrollBarEnabled(false);
  setScrollingCacheEnabled(false);
  setCacheColorHint(Color.TRANSPARENT);
  setFadingEdgeLength(0);
  setOverScrollMode(OVER_SCROLL_NEVER);
  setDividerHeight(0);
  setAdapter(mAdapter);
  setOnScrollListener(new OnScrollListener() {
   @Override
   public void onScrollStateChanged(AbsListView view, int scrollState) {
    if (scrollState == SCROLL_STATE_IDLE) {
     View itemView = getChildAt(0);
     if (itemView != null) {
      float deltaY = itemView.getY();
      if (deltaY == 0) {
       return;
      }
      if (Math.abs(deltaY) < mItemHeight / 2) {
       smoothScrollBy(getDistance(deltaY), 50);
      } else {
       smoothScrollBy(getDistance(mItemHeight + deltaY), 50);
      }
     }
    }
   }
   @Override
   public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount,
     int totalItemCount) {
    refreshItems();
   }
  });
 }
 private int getDistance(float scrollDistance) {
  if (Math.abs(scrollDistance) <= 2) {
   return (int) scrollDistance;
  } else if (Math.abs(scrollDistance) < 12) {
   return scrollDistance > 0 ? 2 : -2;
  } else {
   return (int) (scrollDistance / 6);
  }
 }
 private void refreshItems() {
  int offset = mWheelSize / 2;
  int firstPosition = getFirstVisiblePosition();
  int position = 0;
  if (getChildAt(0) == null) {
   return;
  }
  if (Math.abs(getChildAt(0).getY()) <= mItemHeight / 2) {
   position = firstPosition + offset;
  } else {
   position = firstPosition + offset + 1;
  }
  if (position == mCurrentPositon) {
   return;
  }
  mCurrentPositon = position;
  if (mItemSelectedListener != null) {
   mItemSelectedListener.onItemSelected(getSelection(), getSelectLabel());
  }
  resetItems(firstPosition, position, offset);
 }
 private void resetItems(int firstPosition, int position, int offset){
  for (int i = position - offset - 1; i < position + offset + 1; i++) {
   View itemView = getChildAt(i - firstPosition);
   if (itemView == null) {
    continue;
   }
   TextView labelTv = (TextView) itemView.findViewById(mItemLabelTvId);
   if (position == i) {
    labelTv.setTextColor(mLabelSelectColor);
    itemView.setAlpha(1f);
   } else {
    labelTv.setTextColor(mLabelColor);
    int delta = Math.abs(i - position);
    double alpha = Math.pow(mAlphaGradual, delta);
    itemView.setAlpha((float) alpha);
   }
  }
 }
 
 public void setLabels(List<String> labels) {
  mLabels = labels;
  mAdapter.setData(mLabels);
  mAdapter.notifyDataSetChanged();
  initView();
 }
 
 public void setOnWheelItemSelectedListener(WheelItemSelectedListener mItemSelectedListener) {
  this.mItemSelectedListener = mItemSelectedListener;
 }
 
 public List<String> getLabels() {
  return mLabels;
 }
 
 public void setCycleEnable(boolean enable) {
  if (cylceEnable != enable) {
   cylceEnable = enable;
   mAdapter.notifyDataSetChanged();
   setSelection(getSelection());
  }
 }
 
 @Override
 public void setSelection(final int position) {
  mHandler.post(new Runnable() {
   @Override
   public void run() {
    CycleWheelView.super.setSelection(getPosition(position));
   }
  });
 }
 private int getPosition(int positon) {
  if (mLabels == null || mLabels.size() == 0) {
   return 0;
  }
  if (cylceEnable) {
   int d = Integer.MAX_VALUE / 2 / mLabels.size();
   return positon + d * mLabels.size();
  }
  return positon;
 }
 
 public int getSelection() {
  if (mCurrentPositon == 0) {
   mCurrentPositon = mWheelSize / 2;
  }
  return (mCurrentPositon - mWheelSize / 2) % mLabels.size();
 }
 
 public String getSelectLabel() {
  int position = getSelection();
  position = position < 0 ? 0 : position;
  try {
   return mLabels.get(position);
  } catch (Exception e) {
   return "";
  }
 }
 
 public void setWheelItemLayout(int itemResId, int labelTvId) {
  mItemLayoutId = itemResId;
  mItemLabelTvId = labelTvId;
  mAdapter = new CycleWheelViewAdapter();
  mAdapter.setData(mLabels);
  setAdapter(mAdapter);
  initView();
 }
 
 public void setLabelColor(int labelColor) {
  this.mLabelColor = labelColor;
  resetItems(getFirstVisiblePosition(), mCurrentPositon, mWheelSize/2);
 }
 
 public void setLabelSelectColor(int labelSelectColor) {
  this.mLabelSelectColor = labelSelectColor;
  resetItems(getFirstVisiblePosition(), mCurrentPositon, mWheelSize/2);
 }
 
 public void setAlphaGradual(float alphaGradual) {
  this.mAlphaGradual = alphaGradual;
  resetItems(getFirstVisiblePosition(), mCurrentPositon, mWheelSize/2);
 }
 
 public void setWheelSize(int wheelSize) throws CycleWheelViewException {
  if (wheelSize < 3 || wheelSize % 2 != 1) {
   throw new CycleWheelViewException("Wheel Size Error , Must Be 3,5,7,9...");
  } else {
   mWheelSize = wheelSize;
   initView();
  }
 }
 
 public void setSolid(int unselectedSolidColor, int selectedSolidColor){
  this.solidColor = unselectedSolidColor;
  this.seletedSolidColor = selectedSolidColor;
  initView();
 }
 
 public void setDivider(int dividerColor, int dividerHeight){
  this.dividerColor = dividerColor;
  this.dividerHeight = dividerHeight;
 }
 @SuppressWarnings("deprecation")
 private void initView() {
  mItemHeight = measureHeight();
  ViewGroup.LayoutParams lp = getLayoutParams();
  lp.height = mItemHeight * mWheelSize;
  mAdapter.setData(mLabels);
  mAdapter.notifyDataSetChanged();
  Drawable backgroud = new Drawable() {
   @Override
   public void draw(Canvas canvas) {
    int viewWidth = getWidth();
    Paint dividerPaint = new Paint();
    dividerPaint.setColor(dividerColor);
    dividerPaint.setStrokeWidth(dividerHeight);
    Paint seletedSolidPaint = new Paint();
    seletedSolidPaint.setColor(seletedSolidColor);
    Paint solidPaint = new Paint();
    solidPaint.setColor(solidColor);
    canvas.drawRect(0, 0, viewWidth, mItemHeight * (mWheelSize / 2), solidPaint);
    canvas.drawRect(0, mItemHeight * (mWheelSize / 2 + 1), viewWidth, mItemHeight
      * (mWheelSize), solidPaint);
    canvas.drawRect(0, mItemHeight * (mWheelSize / 2), viewWidth, mItemHeight
      * (mWheelSize / 2 + 1), seletedSolidPaint);
    canvas.drawLine(0, mItemHeight * (mWheelSize / 2), viewWidth, mItemHeight
      * (mWheelSize / 2), dividerPaint);
    canvas.drawLine(0, mItemHeight * (mWheelSize / 2 + 1), viewWidth, mItemHeight
      * (mWheelSize / 2 + 1), dividerPaint);
   }
   @Override
   public void setAlpha(int alpha) {
   }
   @Override
   public void setColorFilter(ColorFilter cf) {
   }
   @Override
   public int getOpacity() {
    return 0;
   }
  };
  setBackgroundDrawable(backgroud);
 }
 private int measureHeight() {
  View itemView = LayoutInflater.from(getContext()).inflate(mItemLayoutId, null);
  itemView.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
    ViewGroup.LayoutParams.WRAP_CONTENT));
  int w = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
  int h = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
  itemView.measure(w, h);
  int height = itemView.getMeasuredHeight();
  // int width = view.getMeasuredWidth();
  return height;
 }
 public interface WheelItemSelectedListener {
  public void onItemSelected(int position, String label);
 }
 public class CycleWheelViewException extends Exception {
  private static final long serialVersionUID = 1L;
  public CycleWheelViewException(String detailMessage) {
   super(detailMessage);
  }
 }
 public class CycleWheelViewAdapter extends BaseAdapter {
  private List<String> mData = new ArrayList<String>();
  public void setData(List<String> mWheelLabels) {
   mData.clear();
   mData.addAll(mWheelLabels);
  }
  @Override
  public int getCount() {
   if (cylceEnable) {
    return Integer.MAX_VALUE;
   }
   return mData.size() + mWheelSize - 1;
  }
  @Override
  public Object getItem(int position) {
   return "";
  }
  @Override
  public long getItemId(int position) {
   return position;
  }
  @Override
  public boolean isEnabled(int position) {
   return false;
  }
  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
   if (convertView == null) {
    convertView = LayoutInflater.from(getContext()).inflate(mItemLayoutId, null);
   }
   TextView textView = (TextView) convertView.findViewById(mItemLabelTvId);
   if (position < mWheelSize / 2
     || (!cylceEnable && position >= mData.size() + mWheelSize / 2)) {
    textView.setText("");
    convertView.setVisibility(View.INVISIBLE);
   } else {
    textView.setText(mData.get((position - mWheelSize / 2) % mData.size()));
    convertView.setVisibility(View.VISIBLE);
   }
   return convertView;
  }
 }
}

 

MainActivity.java: 

public class MainActivity extends Activity {
 private CycleWheelView cycleWheelView0,cycleWheelView1, cycleWheelView2;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  cycleWheelView0 = (CycleWheelView) findViewById(R.id.cycleWheelView);
  List<String> labels = new ArrayList<>();
  for (int i = 0; i < 12; i++) {
   labels.add("" + i);
  }
  cycleWheelView0.setLabels(labels);
  cycleWheelView0.setAlphaGradual(0.5f);
  cycleWheelView0.setOnWheelItemSelectedListener(new WheelItemSelectedListener() {
   @Override
   public void onItemSelected(int position, String label) {
    Log.d("test", label);
   }
  });
  cycleWheelView1 = (CycleWheelView) findViewById(R.id.cycleWheelView1);
  List<String> labels1 = new ArrayList<>();
  for (int i = 0; i < 24; i++) {
   labels1.add("" + i);
  }
  cycleWheelView1.setLabels(labels1);
  try {
   cycleWheelView1.setWheelSize(5);
  } catch (CycleWheelViewException e) {
   e.printStackTrace();
  }
  cycleWheelView1.setSelection(2);
  cycleWheelView1.setWheelItemLayout(R.layout.item_cyclewheel_custom, R.id.tv_label_item_wheel_custom);
  cycleWheelView1.setOnWheelItemSelectedListener(new WheelItemSelectedListener() {
   @Override
   public void onItemSelected(int position, String label) {
    Log.d("test", label);
   }
  });
  cycleWheelView2 = (CycleWheelView) findViewById(R.id.cycleWheelView2);
  List<String> labels2 = new ArrayList<>();
  for (int i = 0; i < 60; i++) {
   labels2.add("" + i);
  }
  cycleWheelView2.setLabels(labels2);
  try {
   cycleWheelView2.setWheelSize(7);
  } catch (CycleWheelViewException e) {
   e.printStackTrace();
  }
  cycleWheelView2.setCycleEnable(true);
  cycleWheelView2.setSelection(30);
  cycleWheelView2.setAlphaGradual(0.6f);
  cycleWheelView2.setDivider(Color.parseColor("#abcdef"), 2);
  cycleWheelView2.setSolid(Color.WHITE,Color.WHITE);
  cycleWheelView2.setLabelColor(Color.BLUE);
  cycleWheelView2.setLabelSelectColor(Color.RED);
  cycleWheelView2.setOnWheelItemSelectedListener(new WheelItemSelectedListener() {
   @Override
   public void onItemSelected(int position, String label) {
    Log.d("test", label);
   }
  });
 }
}

Item_cyclewheel.xml: 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:padding="16dp"
 android:background="@android:color/transparent" >
 <TextView
  android:id="@+id/tv_label_item_wheel"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:textSize="20sp"
  android:singleLine="true"
  android:layout_centerHorizontal="true"
  android:layout_centerVertical="true" />
</RelativeLayout>

Item_cyclewheel_custom.xml: 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:padding="16dp"
 android:background="@android:color/transparent" >
 <TextView
  android:id="@+id/tv_label_item_wheel_custom"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:singleLine="true"
  android:layout_alignParentLeft="true"
  android:layout_centerVertical="true" />
 <ImageView
  android:layout_width="25dp"
  android:layout_height="25dp"
  android:layout_centerVertical="true"
  android:layout_alignParentRight="true"
  android:src="@drawable/ic_launcher" />
</RelativeLayout>

activity_main.xml: 

<LinearLayout 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"
 android:orientation="horizontal" >
 <com.example.wheelviewdemo.CycleWheelView
  android:id="@+id/cycleWheelView"
  android:layout_width="0dp"
  android:layout_height="wrap_content"
  android:layout_weight="1" >
 </com.example.wheelviewdemo.CycleWheelView>
 <com.example.wheelviewdemo.CycleWheelView
  android:id="@+id/cycleWheelView1"
  android:layout_width="0dp"
  android:layout_height="wrap_content"
  android:layout_weight="1" >
 </com.example.wheelviewdemo.CycleWheelView>
 <com.example.wheelviewdemo.CycleWheelView
  android:id="@+id/cycleWheelView2"
  android:layout_width="0dp"
  android:layout_height="wrap_content"
  android:layout_weight="1" >
 </com.example.wheelviewdemo.CycleWheelView>
</LinearLayout>

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