小编给大家分享一下iOS如何自定义时间滚动选择控件，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！
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具体内容如下
1.先上自定义的控件：
/** * 滚轮选择器 * author LH * data 2016/8/20 17:26 */public class WheelView extends View { public static final String TAG = "WheelView"; /** * 自动回滚到中间的速度 */ public static final float SPEED = 2; /** * 除选中item外，上下各需要显示的备选项数目 */ public static final int SHOW_SIZE = 1; private Context context; private List itemList; private int itemCount; /** * item高度 */ private int itemHeight = 50; /** * 选中的位置，这个位置是mDataList的中心位置，一直不变 */ private int currentItem; private Paint selectPaint; private Paint mPaint; // 画背景图中单独的画笔 private Paint centerLinePaint; private float centerY; private float centerX; private float mLastDownY; /** * 滑动的距离 */ private float mMoveLen = 0; private boolean isInit = false; private SelectListener mSelectListener; private Timer timer; private MyTimerTask mTask; Handler updateHandler = new Handler() { @Override public void handleMessage(Message msg) { if (Math.abs(mMoveLen) < SPEED) { // 如果偏移量少于最少偏移量 mMoveLen = 0; if (null != timer) { timer.cancel(); timer.purge(); timer = null; } if (mTask != null) { mTask.cancel(); mTask = null; performSelect(); } } else { // 这里mMoveLen / Math.abs(mMoveLen)是为了保有mMoveLen的正负号，以实现上滚或下滚 mMoveLen = mMoveLen - mMoveLen / Math.abs(mMoveLen) * SPEED; } invalidate(); } }; public WheelView(Context context) { super(context); init(context); } public WheelView(Context context, AttributeSet attrs) { super(context, attrs); init(context); } public void setOnSelectListener(SelectListener listener) { mSelectListener = listener; } public void setWheelStyle(int style) { itemList = WheelStyle.getItemList(context, style); if (itemList != null) { itemCount = itemList.size(); resetCurrentSelect(); invalidate(); } else { Log.i(TAG, "item is null"); } } public void setWheelItemList(List itemList) { this.itemList = itemList; if (itemList != null) { itemCount = itemList.size(); resetCurrentSelect(); } else { Log.i(TAG, "item is null"); } } private void resetCurrentSelect() { if (currentItem < 0) { currentItem = 0; } while (currentItem >= itemCount) { currentItem--; } if (currentItem >= 0 && currentItem < itemCount) { invalidate(); } else { Log.i(TAG, "current item is invalid"); } } public int getItemCount() { return itemCount; } /** * 选择选中的item的index * author LH * data 2016/9/4 11:09 */ public void setCurrentItem(int selected) { currentItem = selected; resetCurrentSelect(); } public int getCurrentItem() { return currentItem; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int mViewHeight = getMeasuredHeight(); int mViewWidth = getMeasuredWidth(); centerX = (float) (mViewWidth / 2.0); centerY = (float) (mViewHeight / 2.0); isInit = true; invalidate(); } private void init(Context context) { this.context = context; timer = new Timer(); itemList = new ArrayList<>(); mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mPaint.setStyle(Style.FILL); mPaint.setTextAlign(Align.CENTER); mPaint.setColor(getResources().getColor(R.color.wheel_unselect_text)); int size1 = (int) (SupportDisplay.getLayoutScale()*22+0.5); mPaint.setTextSize(size1); selectPaint = new Paint(Paint.ANTI_ALIAS_FLAG); selectPaint.setStyle(Style.FILL); selectPaint.setTextAlign(Align.CENTER); selectPaint.setColor(getResources().getColor(R.color.color_1a1a1a)); int size2 = (int) (SupportDisplay.getLayoutScale()*24+0.5); selectPaint.setTextSize(size2); centerLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG); centerLinePaint.setStyle(Style.FILL); centerLinePaint.setTextAlign(Align.CENTER); centerLinePaint.setColor(getResources().getColor(R.color.wheel_unselect_text)); // 绘制背景 setBackground(null); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); if (isInit) { drawData(canvas); } } private void drawData(Canvas canvas) { // 先绘制选中的text再往上往下绘制其余的text if (!itemList.isEmpty()) { // 绘制中间data drawCenterText(canvas); // 绘制上方data for (int i = 1; i < SHOW_SIZE + 1; i++) { drawOtherText(canvas, i, -1); } // 绘制下方data for (int i = 1; i < SHOW_SIZE + 1; i++) { drawOtherText(canvas, i, 1); } } } private void drawCenterText(Canvas canvas) { // 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 float y = centerY + mMoveLen; FontMetricsInt fmi = selectPaint.getFontMetricsInt(); float baseline = (float) (y - (fmi.bottom / 2.0 + fmi.top / 2.0)); canvas.drawText(itemList.get(currentItem), centerX, baseline, selectPaint); } /** * 绘制文本 * author LH * data 2016/9/4 11:10 * @param canvas 画布 * @param position 距离mCurrentSelected的差值 * @param type 1表示向下绘制，-1表示向上绘制 */ private void drawOtherText(Canvas canvas, int position, int type) { int index = currentItem + type * position; if (index >= itemCount) { index = index - itemCount; } if (index < 0) { index = index + itemCount; } String text = itemList.get(index); int itemHeight = getHeight() / (SHOW_SIZE * 2 + 1); float d = itemHeight * position + type * mMoveLen; float y = centerY + type * d; FontMetricsInt fmi = mPaint.getFontMetricsInt(); float baseline = (float) (y - (fmi.bottom / 2.0 + fmi.top / 2.0)); canvas.drawText(text, centerX, baseline, mPaint); } @Override public void setBackground(Drawable background) { background = new Drawable() { @Override public void draw(Canvas canvas) { itemHeight = getHeight() / (SHOW_SIZE * 2 + 1); int width = getWidth(); canvas.drawLine(0, itemHeight, width, itemHeight, centerLinePaint); canvas.drawLine(0, itemHeight * 2, width, itemHeight * 2, centerLinePaint); centerLinePaint.setColor(getResources().getColor(R.color.wheel_bg)); Rect topRect = new Rect(0, 0, width, itemHeight); canvas.drawRect(topRect, centerLinePaint); Rect bottomRect = new Rect(0, itemHeight * 2, width, itemHeight * 3); canvas.drawRect(bottomRect, centerLinePaint); } @Override public void setAlpha(int alpha) { } @Override public void setColorFilter(ColorFilter cf) { } @Override public int getOpacity() { return 0; } }; super.setBackground(background); } @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getActionMasked()) { case MotionEvent.ACTION_DOWN: doDown(event); break; case MotionEvent.ACTION_MOVE: doMove(event); break; case MotionEvent.ACTION_UP: doUp(); break; default: break; } return true; } private void doDown(MotionEvent event) { if (mTask != null) { mTask.cancel(); mTask = null; } mLastDownY = event.getY(); } private void doMove(MotionEvent event) { mMoveLen += (event.getY() - mLastDownY); if (mMoveLen > itemHeight / 2) { // 往下滑超过离开距离 mMoveLen = mMoveLen - itemHeight; currentItem--; if (currentItem < 0) { currentItem = itemCount - 1; } } else if (mMoveLen < -itemHeight / 2) { // 往上滑超过离开距离 mMoveLen = mMoveLen + itemHeight; currentItem++; if (currentItem >= itemCount) { currentItem = 0; } } mLastDownY = event.getY(); invalidate(); } private void doUp() { // 抬起手后mCurrentSelected的位置由当前位置move到中间选中位置 if (Math.abs(mMoveLen) < 0.0001) { mMoveLen = 0; return; } if (mTask != null) { mTask.cancel(); mTask = null; } if (null == timer) { timer = new Timer(); } mTask = new MyTimerTask(updateHandler); timer.schedule(mTask, 0, 10); } class MyTimerTask extends TimerTask { Handler handler; public MyTimerTask(Handler handler) { this.handler = handler; } @Override public void run() { handler.sendMessage(handler.obtainMessage()); } } private void performSelect() { if (mSelectListener != null) { mSelectListener.onSelect(currentItem, itemList.get(currentItem)); } else { Log.i(TAG, "null listener"); } } public interface SelectListener { void onSelect(int index, String text); }}
2.然后是时间选择控件的样式工具类
/** * 时间选择样式 * author LH * data 2016/9/4 11:05 */public class WheelStyle { public static final int minYear = 1980; public static final int maxYear = 2020; /** * Wheel Style Hour */ public static final int STYLE_HOUR = 1; /** * Wheel Style Minute */ public static final int STYLE_MINUTE = 2; /** * Wheel Style Year */ public static final int STYLE_YEAR = 3; /** * Wheel Style Month */ public static final int STYLE_MONTH = 4; /** * Wheel Style Day */ public static final int STYLE_DAY = 5; /** * Wheel Style Simple Day */ public static final int STYLE_SIMPLE_DAY = 6; /** * Wheel Style Set Warn */ public static final int STYLE_SET_WARN = 7; /** * Wheel Style Work Answer */ public static final int STYLE_WORK_ANSWER = 8; private WheelStyle() { } public static List getItemList(Context context, int Style) { if (Style == STYLE_HOUR) { return createHourString(); } else if (Style == STYLE_MINUTE) { return createMinuteString(); } else if (Style == STYLE_YEAR) { return createYearString(); } else if (Style == STYLE_MONTH) { return createMonthString(); } else if (Style == STYLE_DAY) { return createDayString(); } else if (Style == STYLE_SIMPLE_DAY) { return createSimpleDayString(); } else if (Style == STYLE_SET_WARN) { return createSetWarnTimeString(); } else { throw new IllegalArgumentException("style is illegal"); } } private static List createHourString() { List wheelString = new ArrayList<>(); for (int i = 0; i < 24; i++) { wheelString.add(String.format("%02d" + "时", i)); } return wheelString; } private static List createMinuteString() { List wheelString = new ArrayList<>(); for (int i = 0; i < 60; i++) { wheelString.add(String.format("%02d" + "分", i)); } return wheelString; } private static List createYearString() { List wheelString = new ArrayList<>(); for (int i = minYear; i <= maxYear; i++) { wheelString.add(Integer.toString(i)); } return wheelString; } private static List createMonthString() { List wheelString = new ArrayList<>(); for (int i = 1; i <= 12; i++) { wheelString.add(String.format("%02d" + "月", i)); } return wheelString; } private static List createDayString() { List wheelString = new ArrayList<>(); for (int i = 1; i <= 31; i++) { wheelString.add(String.format("%02d" + "日", i)); } return wheelString; } private static List createSimpleDayString() { List wheelString = new ArrayList<>(); wheelString.add("一天后"); wheelString.add("两天后"); wheelString.add("三天后"); return wheelString; } private static List createSetWarnTimeString() { List wheelString = new ArrayList<>(); wheelString.add("30分钟"); wheelString.add("60分钟"); wheelString.add("90分钟"); wheelString.add("120分钟"); return wheelString; } /** * 计算闰月 * * @param month * @return */ private static boolean isLeapMonth(int month) { return month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12; } /** * 计算闰年 * * @param year * @return */ private static boolean isLeapYear(int year) { return (year % 4 == 0 && year % 100 != 0) || year % 400 == 0; }}
3.使用的xml
4.在Java文件中设置mWheelView.setWheelStyle(WheelStyle.STYLE_YEAR);就可以显示WheelStyle类中设置的类型了。这个类中的样式种类读者可以根据自己的需要自行添加。
5.获取当前选择的项也很简单mWheelView.getCurrentItem();就能获取到控件的当前选择的项。获取到所在的项以后剩下的就是逻辑操作了。
以上是“iOS如何自定义时间滚动选择控件”这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注创新互联行业资讯频道！
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