今天想做一個類似這樣的一個效果,可是UI的模板是參考IOS做的,于是就各種百度各種搜,最后讓我找到了一個仿IOS滾輪的一個Demo,稍微研究了一下,發(fā)上來,大家一起學習,以后也方便我查看,就不用再去百度了,嘿嘿!

仿IOS滾輪效果

首先是一個類,繼承了ScrollView

public class WheelView extends ScrollView {public static final String TAG = WheelView.class.getSimpleName();public static class OnWheelViewListener {public void onSelected(int selectedIndex, String item) {}
}private Context context;private LinearLayout views;public WheelView(Context context) {super(context);init(context);
}public WheelView(Context context, AttributeSet attrs) {super(context, attrs);init(context);
}public WheelView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);init(context);
}//    String[] items;
List<String> items;private List<String> getItems() {return items;
}public void setItems(List<String> list) {if (null == items) {items = new ArrayList<String>();}items.clear();items.addAll(list);// 前面和后面補全for (int i = 0; i < offset; i++) {items.add(0, "");items.add("");}initData();}public static final int OFF_SET_DEFAULT = 1;
int offset = OFF_SET_DEFAULT; // 偏移量（需要在最前面和最后面補全）public int getOffset() {return offset;
}public void setOffset(int offset) {this.offset = offset;
}int displayItemCount; // 每頁顯示的數(shù)量int selectedIndex = 1;private void init(Context context) {this.context = context;Log.d(TAG, "parent: " + this.getParent());this.setVerticalScrollBarEnabled(false);views = new LinearLayout(context);views.setOrientation(LinearLayout.VERTICAL);this.addView(views);scrollerTask = new Runnable() {public void run() {int newY = getScrollY();if (initialY - newY == 0) { // stoppedfinal int remainder = initialY % itemHeight;final int divided = initialY / itemHeight;if (remainder == 0) {selectedIndex = divided + offset;onSeletedCallBack();} else {if (remainder > itemHeight / 2) {WheelView.this.post(new Runnable() {@Overridepublic void run() {WheelView.this.smoothScrollTo(0, initialY - remainder + itemHeight);selectedIndex = divided + offset + 1;onSeletedCallBack();}});} else {WheelView.this.post(new Runnable() {@Overridepublic void run() {WheelView.this.smoothScrollTo(0, initialY - remainder);selectedIndex = divided + offset;onSeletedCallBack();}});}}} else {initialY = getScrollY();WheelView.this.postDelayed(scrollerTask, newCheck);}}};}int initialY;Runnable scrollerTask;
int newCheck = 50;public void startScrollerTask() {initialY = getScrollY();this.postDelayed(scrollerTask, newCheck);
}private void initData() {displayItemCount = offset * 2 + 1;for (String item : items) {views.addView(createView(item));}refreshItemView(0);
}int itemHeight = 0;
/*** 這里可以設(shè)置字體的屬性 大小啦,邊距啦,什么東西都可以在這里設(shè)置;*/
private TextView createView(String item) {TextView tv = new TextView(context);tv.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));tv.setSingleLine(true);// 設(shè)置字體大小為20sptv.setTextSize(TypedValue.COMPLEX_UNIT_SP, 20);// 設(shè)置文字內(nèi)容
    tv.setText(item);// 設(shè)置文字居中
    tv.setGravity(Gravity.CENTER);// 設(shè)置內(nèi)邊距int padding = dip2px(15);tv.setPadding(padding, padding, padding, padding);if (0 == itemHeight) {itemHeight = getViewMeasuredHeight(tv);Log.d(TAG, "itemHeight: " + itemHeight);views.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, itemHeight * displayItemCount));LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) this.getLayoutParams();this.setLayoutParams(new LinearLayout.LayoutParams(lp.width, itemHeight * displayItemCount));}return tv;
}@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {super.onScrollChanged(l, t, oldl, oldt);refreshItemView(t);if (t > oldt) {Log.d(TAG, "向下滾動");scrollDirection = SCROLL_DIRECTION_DOWN;} else {Log.d(TAG, "向上滾動");scrollDirection = SCROLL_DIRECTION_UP;}}private void refreshItemView(int y) {int position = y / itemHeight + offset;int remainder = y % itemHeight;int divided = y / itemHeight;if (remainder == 0) {position = divided + offset;} else {if (remainder > itemHeight / 2) {position = divided + offset + 1;}}int childSize = views.getChildCount();for (int i = 0; i < childSize; i++) {TextView itemView = (TextView) views.getChildAt(i);if (null == itemView) {return;}if (position == i) {itemView.setTextColor(Color.parseColor("#0288ce"));} else {itemView.setTextColor(Color.parseColor("#bbbbbb"));}}
}/*** 獲取選中區(qū)域的邊界*/
int[] selectedAreaBorder;private int[] obtainSelectedAreaBorder() {if (null == selectedAreaBorder) {selectedAreaBorder = new int[2];selectedAreaBorder[0] = itemHeight * offset;selectedAreaBorder[1] = itemHeight * (offset + 1);}return selectedAreaBorder;
}private int scrollDirection = -1;
private static final int SCROLL_DIRECTION_UP = 0;
private static final int SCROLL_DIRECTION_DOWN = 1;Paint paint;
int viewWidth;@Override
public void setBackgroundDrawable(Drawable background) {if (viewWidth == 0) {viewWidth = ((Activity) context).getWindowManager().getDefaultDisplay().getWidth();Log.d(TAG, "viewWidth: " + viewWidth);}if (null == paint) {paint = new Paint();paint.setColor(Color.parseColor("#83cde6"));paint.setStrokeWidth(dip2px(1f));}background = new Drawable() {@Overridepublic void draw(Canvas canvas) {canvas.drawLine(viewWidth * 1 / 6, obtainSelectedAreaBorder()[0], viewWidth * 5 / 6, obtainSelectedAreaBorder()[0], paint);canvas.drawLine(viewWidth * 1 / 6, obtainSelectedAreaBorder()[1], viewWidth * 5 / 6, obtainSelectedAreaBorder()[1], paint);}@Overridepublic void setAlpha(int alpha) {}@Overridepublic void setColorFilter(ColorFilter cf) {}@Overridepublic int getOpacity() {return 0;}};super.setBackgroundDrawable(background);}@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {super.onSizeChanged(w, h, oldw, oldh);Log.d(TAG, "w: " + w + ", h: " + h + ", oldw: " + oldw + ", oldh: " + oldh);viewWidth = w;setBackgroundDrawable(null);
}/*** 選中回調(diào)*/
private void onSeletedCallBack() {if (null != onWheelViewListener) {onWheelViewListener.onSelected(selectedIndex, items.get(selectedIndex));}}public void setSeletion(int position) {final int p = position;selectedIndex = p + offset;this.post(new Runnable() {@Overridepublic void run() {WheelView.this.smoothScrollTo(0, p * itemHeight);}});}public String getSeletedItem() {return items.get(selectedIndex);
}public int getSeletedIndex() {return selectedIndex - offset;
}@Override
public void fling(int velocityY) {super.fling(velocityY / 3);
}@Override
public boolean onTouchEvent(MotionEvent ev) {if (ev.getAction() == MotionEvent.ACTION_UP) {startScrollerTask();}return super.onTouchEvent(ev);
}private OnWheelViewListener onWheelViewListener;public OnWheelViewListener getOnWheelViewListener() {return onWheelViewListener;
}public void setOnWheelViewListener(OnWheelViewListener onWheelViewListener) {this.onWheelViewListener = onWheelViewListener;
}private int dip2px(float dpValue) {final float scale = context.getResources().getDisplayMetrics().density;return (int) (dpValue * scale + 0.5f);
}private int getViewMeasuredHeight(View view) {int width = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);int expandSpec = View.MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2, View.MeasureSpec.AT_MOST);view.measure(width, expandSpec);return view.getMeasuredHeight();
}}

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好的 類的源碼就是這些,對于這個類 我并沒有看懂,但是還是會使用的,大家什么地方也不用關(guān)注,只需要關(guān)注那個createView方法即可

之后就是我們的需要在你的xml中配置這么一段語句,就是調(diào)用這個View啦

<你的包名+WheelViewandroid:id="@+id/wv"android:layout_width="match_parent"android:layout_height="wrap_content" />

?

之后在關(guān)聯(lián)著這個布局的java文件中findViewByID得到它

 // 初始化仿IOS滾輪效果的數(shù)據(jù)// 在這里可以設(shè)置滾輪的偏移量 mWheelView.setOffset(2);//設(shè)置每一個Item中的數(shù)據(jù) mArrayList中裝著的是一堆String字符串
        mWheelView.setItems(mArrayList);mWheelView.setOnWheelViewListener(new WheelView.OnWheelViewListener() {@Overridepublic void onSelected(int selectedIndex, String item) {//selectedIndex當前高亮的位置//item當前高亮的位置的內(nèi)容
        }});

?

然后 這樣 這個仿IOS的滾輪效果就實現(xiàn)了...最后附上我查閱到這個仿IOS滾輪效果的原地址

http://www.cnblogs.com/tiantianbyconan/p/3819304.html

轉(zhuǎn)載于:https://www.cnblogs.com/redwolf/p/5295392.html

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