This article will share with you how to implement a custom ring-shaped time wheel. It has certain reference value. Friends in need can refer to it
Let’s take a look at the final effect first:
Function introduction: Any day and week within a year can be matched , other days and months are not limited to years
Implementation principle: Use a custom scroll wheel to write the logical parts corresponding to the day, week and month
The source code of the custom view is as follows:
package com.lwyy.wheel.view;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import com.lwyy.wheel.R;
import java.util.ArrayList;
import java.util.List;
/**
* Created by ll on 2017/9/25.
*/
public class CircleWheelView extends View {
private static final String TAG = CircleWheelView.class.getSimpleName();
private int mItemAlign;
public static final int ALIGN_CENTER = 0, ALIGN_LEFT = 1, ALIGN_RIGHT = 2;
private Paint mPaint;
private OnItemSelectedListener mOnItemSelectedListener;
private int mTextMaxWidth, mTextMaxHeight;
private Rect mRectDrawn;
private int mDrawnCenterX, mDrawnCenterY; //滚轮选择器绘制中心坐标
private int mWheelCenterX, mWheelCenterY; //滚轮选择器中心坐标
private int mItemTextColor, mSelectedItemTextColor; //数据项文本颜色以及被选中的数据项文本颜色
private int mItemHeight;
private float mItemTextSize;
private int mLastPointY; //用户手指上一次触摸事件发生时事件Y坐标
private float moveY;
private List mData = new ArrayList();
private List mDataCC = new ArrayList();
private int mTurnToCenterX;
private int mCurrentItemPosition;
private int mDefaultHalfNum = 7, mDefaultVisibleNum = 13; //设置当前view默认可见的item个数
private int mVisibleHalfNum, mVisibleCount; //视图区域内的展示的item个数
private int mDataSize;
private boolean isCyclic; //数据是否循环展示 针对list的数目小于mDefaultVisibleNum
private boolean isLoopDisplay; //所有的数据是否是球形展示,即永远的头尾衔接,如果isCyclic是true,则该值也是true
private float[] rates = null;
private float[] textSizeRates = null;
public CircleWheelView(Context context) {
this(context, null);
}
public CircleWheelView(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CircleWheelView);
mItemTextSize = a.getDimensionPixelSize(R.styleable.CircleWheelView_wheel_item_text_size,
getResources().getDimensionPixelSize(R.dimen.WheelItemTextSize_Default));
mItemAlign = a.getInt(R.styleable.CircleWheelView_wheel_item_align, ALIGN_CENTER);
mItemTextColor = a.getColor(R.styleable.CircleWheelView_wheel_item_text_color, 0xFF888888);
mSelectedItemTextColor = a.getColor(R.styleable.CircleWheelView_wheel_selected_item_text_color, 0xFF888899);
mTurnToCenterX = a.getInt(R.styleable.CircleWheelView_wheel_turn_to_centerx, 0); //转向中间,偏移的距离
isCyclic = a.getBoolean(R.styleable.CircleWheelView_wheel_cyclic, false);
isLoopDisplay = a.getBoolean(R.styleable.CircleWheelView_wheel_loop_display, false);
a.recycle();
mPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG | Paint.LINEAR_TEXT_FLAG);
mPaint.setStyle(Paint.Style.FILL);
mRectDrawn = new Rect();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
int modeHeight = MeasureSpec.getMode(heightMeasureSpec);
int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);
// 计算原始内容尺寸
int resultWidth = mTextMaxWidth;
int resultHeight = mTextMaxHeight * mVisibleCount;
// 考虑内边距对尺寸的影响
resultWidth += getPaddingLeft() + getPaddingRight();
resultHeight += getPaddingTop();
// 考虑父容器对尺寸的影响
resultWidth = measureSize(modeWidth, sizeWidth, resultWidth);
resultHeight = measureSize(modeHeight, sizeHeight, resultHeight);
setMeasuredDimension(resultWidth, resultHeight);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
// 获取内容区域中心坐标
mRectDrawn.set(getPaddingLeft(), getPaddingTop(), getWidth() - getPaddingRight(),
getHeight() - getPaddingBottom());
mWheelCenterX = mRectDrawn.centerX();
mWheelCenterY = mRectDrawn.centerY();
computeDrawnCenter();
}
@Override
protected void onDraw(Canvas canvas) {
if (mDataCC.size() > 0) {
mPaint.setStrokeWidth(1);
mPaint.setSubpixelText(true); //设置该项为true，将有助于文本在LCD屏幕上的显示效果
canvas.save();
int indexBottom = 0;
float distanceX = 0, mDrawnItemCenterY = 0;
int endIndex = isCyclic ? 13 : Math.min(mDefaultVisibleNum, mDataCC.size());
if (endIndex > mData.size())
endIndex = mData.size();
for (int i = 0; i < endIndex; i++) {
if (i == 0) mPaint.setColor(mSelectedItemTextColor);
else mPaint.setColor(mItemTextColor);
if (isCyclic) {
if (i < mVisibleHalfNum)
indexBottom = i;
else
indexBottom = i - mVisibleHalfNum + 1;
if (i < mVisibleHalfNum)
mDrawnItemCenterY = (int) (mDrawnCenterY - (mItemHeight * rates[indexBottom]));
else
mDrawnItemCenterY = (int) (mDrawnCenterY + (mItemHeight * rates[indexBottom]));
if (i == endIndex - 1)
mDrawnItemCenterY = (int) (mDrawnCenterY + (mItemHeight * rates[indexBottom]) - 10);
} else if (mData.size() < 13) { if (i < mVisibleHalfNum + 1)
indexBottom = i; else
indexBottom = i - mVisibleHalfNum; if (i < mVisibleHalfNum + 1)
mDrawnItemCenterY = (int) (mDrawnCenterY - (mItemHeight * rates[indexBottom])); else
mDrawnItemCenterY = (int) (mDrawnCenterY + (mItemHeight * rates[indexBottom])); if (i == endIndex - 1)
mDrawnItemCenterY = (int) (mDrawnCenterY + (mItemHeight * rates[indexBottom]) - 10);// if (i < mVisibleHalfNum)// indexBottom = i;// else// indexBottom = i - mVisibleHalfNum + 1;//// if (i < mVisibleHalfNum)// mDrawnItemCenterY = (int) (mDrawnCenterY - (mItemHeight * rates[indexBottom]));// else// mDrawnItemCenterY = (int) (mDrawnCenterY + (mItemHeight * rates[indexBottom]));// if (i == endIndex - 1)// mDrawnItemCenterY = (int) (mDrawnCenterY + (mItemHeight * rates[indexBottom]) - 10);
} else {
if (i < mVisibleHalfNum)
indexBottom = i;
else
indexBottom = i - mVisibleHalfNum + 1;
// LogUtil.e(TAG, "indexBottom:" + indexBottom + ",mVisibleHalfNum:" + mVisibleHalfNum + ",i:" + i);
if (indexBottom >= mDefaultHalfNum)
continue;
if (i < mVisibleHalfNum)
mDrawnItemCenterY = (int) (mDrawnCenterY - (mItemHeight * rates[indexBottom])); else
mDrawnItemCenterY = (int) (mDrawnCenterY + (mItemHeight * rates[indexBottom])); if (i == endIndex - 1)
mDrawnItemCenterY = (int) (mDrawnCenterY + (mItemHeight * rates[indexBottom]) - 10);
}
mPaint.setTextSize(mItemTextSize * textSizeRates[indexBottom]);
paintText(canvas, distanceX, rates, mDrawnItemCenterY, indexBottom, i);
}
}
}
private void paintText(Canvas canvas, float distanceX, float[] rates, float drawnCenterY, int indexBottom, int i) {
float mDistanceSubX = mDrawnCenterX - mTurnToCenterX * rates[indexBottom] * rates[indexBottom];
float mDistanceAddX = mDrawnCenterX + mTurnToCenterX * rates[indexBottom] * rates[indexBottom];
switch (mItemAlign) {
case ALIGN_CENTER:
distanceX = mDrawnCenterX;
break;
case ALIGN_LEFT:
distanceX = mData.get(i).toString().length() <= 1 ?
mDistanceSubX + 4 * (mVisibleHalfNum - indexBottom) : mDistanceSubX;
break;
case ALIGN_RIGHT:
distanceX = mData.get(i).toString().length() <= 1 ?
mDistanceAddX - 4 * (mVisibleHalfNum - indexBottom) : mDistanceAddX;
break;
}
String text = "";
if (!isLoopDisplay && !isCyclic && mDataSize > mDefaultHalfNum) {
if (mCurrentItemPosition < mDefaultHalfNum - 1 && (i >= mDefaultHalfNum || i <= mCurrentItemPosition)) {
text = String.valueOf(mData.get(i));
} else if (mCurrentItemPosition > mDefaultHalfNum - 1 && i < mDefaultHalfNum + (mDataSize - mCurrentItemPosition) - 1)
text = String.valueOf(mData.get(i));
else if (mCurrentItemPosition == mDefaultHalfNum - 1)
text = String.valueOf(mData.get(i));
} else if (isCyclic && !isLoopDisplay) {
if (mCurrentItemPosition < mDefaultHalfNum - 1 && ((i >= mDefaultHalfNum && i < mDataCC.size() - mCurrentItemPosition - 1 + mDefaultHalfNum) || i <= mCurrentItemPosition)) {
text = String.valueOf(mData.get(i));
} else if (mCurrentItemPosition > mDefaultHalfNum - 1 && i < mDefaultHalfNum + (mDataCC.size() - mCurrentItemPosition) - 1)
text = String.valueOf(mData.get(i)); else if (mCurrentItemPosition == mDefaultHalfNum - 1 && i < mDataCC.size())
text = String.valueOf(mData.get(i));
} else {
text = String.valueOf(mData.get(i));
// LogUtil.i(TAG, "text:" + mData.get(i) + ",i:" + i);
}
canvas.drawText(text, distanceX, drawnCenterY, mPaint);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
mLastPointY = (int) event.getY();
break;
case MotionEvent.ACTION_MOVE:
moveY = event.getY() - mLastPointY;
if (Math.abs(moveY) < 1) break;
if (mDataCC.size() < mDefaultHalfNum)
break;
if (!isLoopDisplay) {
if (mCurrentItemPosition == 0 && moveY > 0)
break;
if (isCyclic && mDataCC.size() < mDefaultVisibleNum && mCurrentItemPosition == mDataCC.size() - 1 && moveY < 0)
break;
else if (mCurrentItemPosition == mDataSize - 1 && moveY < 0)
break;
}
changeMoveItemPosition(event, mItemHeight * 3 / 2);
break;
case MotionEvent.ACTION_UP:
if (mDataCC.size() < mDefaultHalfNum) {
changeMoveItemPosition(event, mItemHeight / 2);
}
if (null != mOnItemSelectedListener && mCurrentItemPosition < mDataCC.size() && mDataCC.size() > 0 && mCurrentItemPosition >= 0)
mOnItemSelectedListener.onItemSelected(this, mDataCC.get(mCurrentItemPosition), mCurrentItemPosition); break;
}
return true;
}
private void changeMoveItemPosition(MotionEvent event, int moveHeight) {
if (Math.abs(moveY) > moveHeight) {
mLastPointY = (int) event.getY();
if (moveY > 0)
mCurrentItemPosition--;
else
mCurrentItemPosition++;
if (mCurrentItemPosition > mDataCC.size() - 1)
mCurrentItemPosition -= mDataCC.size();
if (mCurrentItemPosition < 0)
mCurrentItemPosition += mDataCC.size();
if (mCurrentItemPosition >= 0 && mCurrentItemPosition < mDataCC.size())
setSelectedItemPosition(mDataCC, mCurrentItemPosition);
}
}
private void computeTextSize() {
mTextMaxWidth = mTextMaxHeight = 0;
for (Object obj : mData) {
String text = String.valueOf(obj);
int width = (int) mPaint.measureText(text);
mTextMaxWidth = Math.max(mTextMaxWidth, width);
}
Paint.FontMetrics metrics = mPaint.getFontMetrics();
mTextMaxHeight = (int) (metrics.bottom - metrics.top);
}
private int measureSize(int mode, int sizeExpect, int sizeActual) {
int realSize; if (mode == MeasureSpec.EXACTLY) {
realSize = sizeExpect;
} else {
realSize = sizeActual; if (mode == MeasureSpec.AT_MOST)
realSize = Math.min(realSize, sizeExpect);
} return realSize;
}
//固定的等比高度
private void computeDrawnCenter() {
int num = 7;
mItemHeight = mRectDrawn.height() / (num * 2 - 2);
mPaint.setTextAlign(Paint.Align.CENTER);
mDrawnCenterX = mWheelCenterX;
mDrawnCenterY = mWheelCenterY + mItemHeight / num;
}
public void updateVisibleItemCount(int num) {
if (isCyclic) {
mVisibleCount = mDefaultVisibleNum = 13;
mVisibleHalfNum = mDefaultHalfNum = 7;
} else {
if (num >= mDefaultHalfNum)
mVisibleHalfNum = mDefaultHalfNum;
else {
mVisibleHalfNum = num % 2 == 1 ? num / 2 + 1 : num / 2;
}
}
// LogUtil.e(TAG, "mVisibleHalfNum:" + mVisibleHalfNum);
mVisibleCount = Math.min(mDefaultVisibleNum, num);
mDataSize = isCyclic ? mDefaultVisibleNum : num;
}
public void setData(List mData, int pos) {
setData(mData, pos, true);
}
public void setData(List mData, int pos, boolean isLoopDisplay) {
setData(mData, pos, isLoopDisplay, false, 13);
}
public void setData(List mData, int pos, boolean isLoopDisplay, boolean isCycle) {
setData(mData, pos, isLoopDisplay, isCycle, 13);
}
/**
* @param mData 传入的展示列表数据
* @param pos 当前view的中间item展示的内容
* @param isLoopDisplay 所有的数据是否是球形展示,即永远的头尾衔接,即item由mDataSize - 1下滑变为0,默认true
* @param isCycle 数据是否循环展示 针对list的数目小于mDefaultVisibleNum. 默认false
* @param visibleShowNum 当前界面展示的item个数
*/
public void setData(List mData, int pos, boolean isLoopDisplay, boolean isCycle, int visibleShowNum) {
if (mData.size() <= 0 || pos < 0 || pos >= mData.size())
return;
if (visibleShowNum % 2 == 1)
visibleShowNum++;
if (mData.size() > 12 && isCycle)
isCycle = false;
else if (mData.size() < 13 && !isCycle && !isLoopDisplay) {
isCycle = true;
}
mDefaultVisibleNum = mData.size() < 13 && !isCycle ? mData.size() : 13;
mDefaultHalfNum = mDefaultVisibleNum < 13 ? mDefaultVisibleNum / 2 : 7;
this.isLoopDisplay = isLoopDisplay;
this.isCyclic = isCycle;
if (this.mDataCC.size() > 0)
this.mDataCC.clear();
this.mDataCC.addAll(mData);
this.mCurrentItemPosition = pos;
updateVisibleItemCount(mData.size());
setSelectedItemPosition(mData, pos);
updateRates();
computeTextSize();
requestLayout();
invalidate();
}
public void updateDataPos(int pos) {
if (pos < 0)
return;
if (pos >= mDataCC.size())
pos = mDataCC.size() / 2 - 1;
this.mCurrentItemPosition = pos;
setSelectedItemPosition(mDataCC, pos);
invalidate();
}
private void updateRates() {
int num = 7;
if (null == rates)
rates = new float[num];
if (null == textSizeRates)
textSizeRates = new float[num];
float rate = 0.0f;
for (int i = 0; i < num; i++) {
if (i > 0) {
rate = (3 * (11 * i - (i - 1) * (i - 1))) / 22f;
if (i == num - 1)
rate = (3 * (11 * i - (i - 1) * (i - 1)) + 4) / 22f;
}
rates[i] = rate;
textSizeRates[i] = ((18 - 7 * i / 3) / 13f);
}
}
public void setItemAlign(int align) {
this.mItemAlign = align;
invalidate();
}
public void setTurnToCenter(int turnToCenterX) {
this.mTurnToCenterX = turnToCenterX;
requestLayout();
invalidate();
}
public void setSelectedItemPosition(List mDatas, int centerPos) {
if (mData.size() > 0)
mData.clear();
mDataSize = isCyclic ? mDefaultVisibleNum : mDatas.size();
int halfIndex = isCyclic ? 7 : Math.min(mVisibleHalfNum, mDefaultHalfNum);
// LogUtil.i(TAG, "endIndex:" + endIndex + ",topPos:" + topPos + ",centerPos:" + centerPos + ",bottomPos:" + bottomPos + ",halfIndex:" + halfIndex);
// LogUtil.i(TAG, "endIndex:" + endIndex + ",mVisibleHalfNum:" + mVisibleHalfNum + ",mDefaultHalfNum:" + mDefaultHalfNum + ",mDefaultVisibleNum:" + mDefaultVisibleNum);
int bottom = 0;
mData.add(0, mDatas.get(centerPos));
if ((isCyclic && mDatas.size() < 13) || mDatas.size() >= 13) {
for (int i = 1; i < halfIndex; i++) {
bottom = centerPos - i;
bottom = chooseIndex(bottom, mDatas.size());
mData.add(mDatas.get(bottom));
}
for (int i = mDatas.size() - 1; i >= halfIndex; i--) {
bottom = centerPos + mDatas.size() - i;
bottom = chooseIndex(bottom, mDatas.size());
mData.add(mDatas.get(bottom));
}
if (isCyclic)
for (int i = mDatas.size(); i < 13; i++) {
bottom = i - halfIndex + 1 + centerPos;
bottom = chooseIndex(bottom, mDatas.size());
// LogUtil.e(TAG, "bottom:" + bottom + ",:" + mDatas.get(bottom));
mData.add(mDatas.get(bottom));
}
} else if (mDatas.size() < 13) {
//下面个数比上面多
for (int i = 1; i <= halfIndex; i++) {
bottom = centerPos - i;
bottom = chooseIndex(bottom, mDatas.size());
mData.add(mDatas.get(bottom));
}
for (int i = mDatas.size() - 1; i > halfIndex; i--) {
bottom = centerPos + mDatas.size() - i;
bottom = chooseIndex(bottom, mDatas.size());
mData.add(mDatas.get(bottom));
}
}
invalidate();
}
public void setTextSize(float textSize) {
this.mItemTextSize = textSize;
invalidate();
}
public void setTextSelectColor(int colorRes) {
this.mSelectedItemTextColor = colorRes;
requestLayout();
invalidate();
}
public int chooseIndex(int index, int dataSize) {
if (index > dataSize - 1)
index -= dataSize;
if (index < 0)
index += dataSize;
return index;
}
public void setOnItemSelectedListener(OnItemSelectedListener onItemSelectedListener) {
this.mOnItemSelectedListener = onItemSelectedListener;
}
public int getListSize() {
if (null != mDataCC)
return mDataCC.size();
return 0;
}
/**
* 滚轮选择器Item项被选中时监听接口
*/
public interface OnItemSelectedListener {
void onItemSelected(CircleWheelView view, Object data, int position);
}
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