Android自定义实现循环滚轮控件WheelView

package cc.wxf.view.wheel;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import java.util.ArrayList;import java.util.List;/** * Created by ccwxf on 2016/3/31. */public class WheelView extends View { public static final int FONT_COLOR = Color.BLACK; public static final int FONT_SIZE = 30; public static final int PADDING = 10; public static final int SHOW_COUNT = 3; public static final int SELECT = 0; //总体宽度、高度、Item的高度 private int width; private int height; private int itemHeight; //需要显示的行数 private int showCount = SHOW_COUNT; //当前默认选择的位置 private int select = SELECT; //字体颜色、大小、补白 private int fontColor = FONT_COLOR; private int fontSize = FONT_SIZE; private int padding = PADDING; //文本列表 private List<String> lists; //选中项的辅助文本，可为空 private String selectTip; //每一项Item和选中项 private List<WheelItem> wheelItems = new ArrayList<WheelItem>(); private WheelSelect wheelSelect = null; //手点击的Y坐标 private float mTouchY; //监听器 private OnWheelViewItemSelectListener listener; public WheelView(Context context) { super(context); } public WheelView(Context context, AttributeSet attrs) { super(context, attrs); } public WheelView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } /** * 设置字体的颜色，不设置的话默认为黑色 * @param fontColor * @return */ public WheelView fontColor(int fontColor){ this.fontColor = fontColor; return this; } /** * 设置字体的大小，不设置的话默认为30 * @param fontSize * @return */ public WheelView fontSize(int fontSize){ this.fontSize = fontSize; return this; } /** * 设置文本到上下两边的补白，不合适的话默认为10 * @param padding * @return */ public WheelView padding(int padding){ this.padding = padding; return this; } /** * 设置选中项的复制文本，可以不设置 * @param selectTip * @return */ public WheelView selectTip(String selectTip){ this.selectTip = selectTip; return this; } /** * 设置文本列表，必须且必须在build方法之前设置 * @param lists * @return */ public WheelView lists(List<String> lists){ this.lists = lists; return this; } /** * 设置显示行数，不设置的话默认为3 * @param showCount * @return */ public WheelView showCount(int showCount){ if(showCount % 2 == 0){  throw new IllegalStateException("the showCount must be odd"); } this.showCount = showCount; return this; } /** * 设置默认选中的文本的索引，不设置默认为0 * @param select * @return */ public WheelView select(int select){ this.select = select; return this; } /** * 最后调用的方法，判断是否有必要函数没有被调用 * @return */ public WheelView build(){ if(lists == null){  throw new IllegalStateException("this method must invoke after the method [lists]"); } return this; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { //得到总体宽度 width = MeasureSpec.getSize(widthMeasureSpec) - getPaddingLeft() - getPaddingRight(); // 得到每一个Item的高度 Paint mPaint = new Paint(); mPaint.setTextSize(fontSize); Paint.FontMetrics metrics = mPaint.getFontMetrics(); itemHeight = (int) (metrics.bottom - metrics.top) + 2 * padding; //初始化每一个WheelItem initWheelItems(width, itemHeight); //初始化WheelSelect wheelSelect = new WheelSelect(showCount / 2 * itemHeight, width, itemHeight, selectTip, fontColor, fontSize, padding); //得到所有的高度 height = itemHeight * showCount; super.onMeasure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY)); } /** * 创建显示个数+2个WheelItem * @param width * @param itemHeight */ private void initWheelItems(int width, int itemHeight) { wheelItems.clear(); for(int i = 0; i < showCount + 2; i++){  int startY = itemHeight * (i - 1);  int stringIndex = select - showCount / 2 - 1 + i;  if(stringIndex < 0){  stringIndex = lists.size() + stringIndex;  }  wheelItems.add(new WheelItem(startY, width, itemHeight, fontColor, fontSize, lists.get(stringIndex))); } } @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()){  case MotionEvent.ACTION_DOWN:  mTouchY = event.getY();  return true;  case MotionEvent.ACTION_MOVE:  float dy = event.getY() - mTouchY;  mTouchY = event.getY();  handleMove(dy);  break;  case MotionEvent.ACTION_UP:  handleUp();  break; } return super.onTouchEvent(event); } /** * 处理移动操作 * @param dy */ private void handleMove(float dy) { //调整坐标 for(WheelItem item : wheelItems){  item.adjust(dy); } invalidate(); //调整 adjust(); } /** * 处理抬起操作 */ private void handleUp(){ int index = -1; //得到应该选择的那一项 for(int i = 0; i < wheelItems.size(); i++){  WheelItem item = wheelItems.get(i);  //如果startY在selectItem的中点上面，则将该项作为选择项  if(item.getStartY() > wheelSelect.getStartY() && item.getStartY() < (wheelSelect.getStartY() + itemHeight / 2)){  index = i;  break;  }  //如果startY在selectItem的中点下面，则将上一项作为选择项  if(item.getStartY() >= (wheelSelect.getStartY() + itemHeight / 2) && item.getStartY() < (wheelSelect.getStartY() + itemHeight)){  index = i - 1;  break;  } } //如果没找到或者其他因素，直接返回 if(index == -1){  return; } //得到偏移的位移 float dy = wheelSelect.getStartY() - wheelItems.get(index).getStartY(); //调整坐标 for(WheelItem item : wheelItems){  item.adjust(dy); } invalidate(); // 调整 adjust(); //设置选择项 int stringIndex = lists.indexOf(wheelItems.get(index).getText()); if(stringIndex != -1){  select = stringIndex;  if(listener != null){  listener.onItemSelect(select);  } } } /** * 调整Item移动和循环显示 */ private void adjust(){ //如果向下滑动超出半个Item的高度，则调整容器 if(wheelItems.get(0).getStartY() >= -itemHeight / 2 ){  //移除最后一个Item重用  WheelItem item = wheelItems.remove(wheelItems.size() - 1);  //设置起点Y坐标  item.setStartY(wheelItems.get(0).getStartY() - itemHeight);  //得到文本在容器中的索引  int index = lists.indexOf(wheelItems.get(0).getText());  if(index == -1){  return;  }  index -= 1;  if(index < 0){  index = lists.size() + index;  }  //设置文本  item.setText(lists.get(index));  //添加到最开始  wheelItems.add(0, item);  invalidate();  return; } //如果向上滑超出半个Item的高度，则调整容器 if(wheelItems.get(0).getStartY() <= (-itemHeight / 2 - itemHeight)){  //移除第一个Item重用  WheelItem item = wheelItems.remove(0);  //设置起点Y坐标  item.setStartY(wheelItems.get(wheelItems.size() - 1).getStartY() + itemHeight);  //得到文本在容器中的索引  int index = lists.indexOf(wheelItems.get(wheelItems.size() - 1).getText());  if(index == -1){  return;  }  index += 1;  if(index >= lists.size()){  index = 0;  }  //设置文本  item.setText(lists.get(index));  //添加到最后面  wheelItems.add(item);  invalidate();  return; } } /** * 得到当前的选择项 */ public int getSelectItem(){ return select; } @Override protected void onDraw(Canvas canvas) { //绘制每一项Item for(WheelItem item : wheelItems){  item.onDraw(canvas); } //绘制阴影 if(wheelSelect != null){  wheelSelect.onDraw(canvas); } } /** * 设置监听器 * @param listener * @return */ public WheelView listener(OnWheelViewItemSelectListener listener){ this.listener = listener; return this; } public interface OnWheelViewItemSelectListener{ void onItemSelect(int index); }}

package cc.wxf.view.wheel;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.RectF;/** * Created by ccwxf on 2016/3/31. */public class WheelItem { // 起点Y坐标、宽度、高度 private float startY; private int width; private int height; //四点坐标 private RectF rect = new RectF(); //字体大小、颜色 private int fontColor; private int fontSize; private String text; private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); public WheelItem(float startY, int width, int height, int fontColor, int fontSize, String text) { this.startY = startY; this.width = width; this.height = height; this.fontColor = fontColor; this.fontSize = fontSize; this.text = text; adjust(0); } /** * 根据Y坐标的变化值，调整四点坐标值 * @param dy */ public void adjust(float dy){ startY += dy; rect.left = 0; rect.top = startY; rect.right = width; rect.bottom = startY + height; } public float getStartY() { return startY; } /** * 直接设置Y坐标属性，调整四点坐标属性 * @param startY */ public void setStartY(float startY) { this.startY = startY; rect.left = 0; rect.top = startY; rect.right = width; rect.bottom = startY + height; } public void setText(String text) { this.text = text; } public String getText() { return text; } public void onDraw(Canvas mCanvas){ //设置钢笔属性 mPaint.setTextSize(fontSize); mPaint.setColor(fontColor); //得到字体的宽度 int textWidth = (int)mPaint.measureText(text); //drawText的绘制起点是左下角,y轴起点为baseLine Paint.FontMetrics metrics = mPaint.getFontMetrics(); int baseLine = (int)(rect.centerY() + (metrics.bottom - metrics.top) / 2 - metrics.bottom); //居中绘制 mCanvas.drawText(text, rect.centerX() - textWidth / 2, baseLine, mPaint); }}

package cc.wxf.view.wheel;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Rect;/** * Created by ccwxf on 2016/4/1. */public class WheelSelect { //黑框背景颜色 public static final int COLOR_BACKGROUND = Color.parseColor("#77777777"); //黑框的Y坐标起点、宽度、高度 private int startY; private int width; private int height; //四点坐标 private Rect rect = new Rect(); //需要选择文本的颜色、大小、补白 private String selectText; private int fontColor; private int fontSize; private int padding; private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); public WheelSelect(int startY, int width, int height, String selectText, int fontColor, int fontSize, int padding) { this.startY = startY; this.width = width; this.height = height; this.selectText = selectText; this.fontColor = fontColor; this.fontSize = fontSize; this.padding = padding; rect.left = 0; rect.top = startY; rect.right = width; rect.bottom = startY + height; } public int getStartY() { return startY; } public void setStartY(int startY) { this.startY = startY; } public void onDraw(Canvas mCanvas) { //绘制背景 mPaint.setStyle(Paint.Style.FILL); mPaint.setColor(COLOR_BACKGROUND); mCanvas.drawRect(rect, mPaint); //绘制提醒文字 if(selectText != null){  //设置钢笔属性  mPaint.setTextSize(fontSize);  mPaint.setColor(fontColor);  //得到字体的宽度  int textWidth = (int)mPaint.measureText(selectText);  //drawText的绘制起点是左下角,y轴起点为baseLine  Paint.FontMetrics metrics = mPaint.getFontMetrics();  int baseLine = (int)(rect.centerY() + (metrics.bottom - metrics.top) / 2 - metrics.bottom);  //在靠右边绘制文本  mCanvas.drawText(selectText, rect.right - padding - textWidth, baseLine, mPaint); } }}

 final WheelView wheelView = (WheelView) findViewById(R.id.wheelView); final List<String> lists = new ArrayList<>(); for(int i = 0; i < 20; i++){  lists.add("test:" + i); } wheelView.lists(lists).fontSize(35).showCount(5).selectTip("年").select(0).listener(new WheelView.OnWheelViewItemSelectListener() {  @Override  public void onItemSelect(int index) {  Log.d("cc", "current select:" + wheelView.getSelectItem() + " index :" + index + ",result=" + lists.get(index));  } }).build();