WheelView
WheelView copied to clipboard
wangjiegulu
minor improvement in refreshItemView function and set OnClickListener on TextView item
-
added itemIndex parameter to createView function
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initData function has been modified
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in createView function setOnClickListener added to tv object
public static final int OFF_SET_DEFAULT = 2;
设置OFF_SET_DEFAULT=2，将组件滚动到最后一个，出现报错： java.lang.IndexOutOfBoundsException: Index 18 out of bounds for length 17
能不能帮忙提供思路
Set OFF_SET_DEFAULT=2 and scroll the component to the last one, and an error message appears java.lang.IndexOutOfBoundsException: Index 18 out of bounds for length 17
Can you help with ideas
我设计的代码：
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);
}
List<String> items;
public void setItems(List<String> list) {
if (items == null) {
items = new ArrayList<>();
}
items.clear();
items.addAll(list);
for (int i = 0; i < offset; i++) {
items.add(0, "");
items.add("");
}
initData();
}
public static final int OFF_SET_DEFAULT = 2;
int offset = OFF_SET_DEFAULT;
int displayItemCount; // 每页显示的数量
int selectedIndex = 1;
private void init(Context context) {
this.context = context;
this.setVerticalScrollBarEnabled(false);
this.setFadingEdgeLength(0);
this.setOverScrollMode(OVER_SCROLL_NEVER);
views = new LinearLayout(context);
views.setOrientation(LinearLayout.VERTICAL);
this.addView(views);
scrollerTask = () -> {
int newY = getScrollY();
if (initialY - newY == 0) { // stopped
final int remainder = initialY % itemHeight;
final int divided = initialY / itemHeight;
if (remainder == 0) {
selectedIndex = divided + offset;
onSeletedCallBack();
} else {
if (remainder > itemHeight / 2) {
WheelView.this.post(() -> {
WheelView.this.smoothScrollTo(0, initialY - remainder + itemHeight);
selectedIndex = divided + offset + 1;
onSeletedCallBack();
});
} else {
WheelView.this.post(() -> {
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 (int i = 0; i < items.size(); i++) {
views.addView(createView(items.get(i), i - offset));
}
refreshItemView(0);
//postDelayed(scrollerTask, newCheck);
}
int itemHeight = 0;
private View createView(String item, int itemIndex) {
TextView tv = new TextView(context);
tv.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
tv.setSingleLine(true);
tv.setTextSize(TypedValue.COMPLEX_UNIT_SP, 20);
tv.setText(item);
tv.setTag(itemIndex);
tv.setGravity(Gravity.CENTER);
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.WRAP_CONTENT,
itemHeight * displayItemCount,
Gravity.CENTER_HORIZONTAL
));
views.setGravity(Gravity.CENTER);
LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) this.getLayoutParams();
this.setLayoutParams(new LinearLayout.LayoutParams(
lp.width,
itemHeight * displayItemCount
));
}
tv.setOnClickListener(v -> {
int itemIndex1 = (int) v.getTag();
setSeletion(itemIndex1);
});
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, "向下滚动"); scrollDirection = SCROLL_DIRECTION_DOWN; } else { // Log.d(TAG, "向上滚动"); scrollDirection = SCROLL_DIRECTION_UP; } }
private void refreshItemView(int y) {
int divided = y / itemHeight;
int remainder = y % itemHeight;
int position = divided + offset;
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"));
}
}
}
/**
* 获取选中区域的边界
*/
int[] selectedAreaBorder;
private int[] obtainSelectedAreaBorder() {
if (null == selectedAreaBorder) {
selectedAreaBorder = new int[2];
selectedAreaBorder[0] = itemHeight * offset;
selectedAreaBorder[1] = itemHeight * (offset + 1);
}
return selectedAreaBorder;
}
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 = views.getWidth();
Log.d(TAG, "viewWidth: " + viewWidth);
}
if (null == paint) {
paint = new Paint();
paint.setColor(Color.parseColor("#83cde6"));
paint.setStrokeWidth(dip2px(1f));
}
background = new Drawable() {
@Override
public void draw(Canvas canvas) {
canvas.drawLine(
(float) (viewWidth) / 6,
obtainSelectedAreaBorder()[0],
(float) (viewWidth * 5) / 6,
obtainSelectedAreaBorder()[0],
paint);
canvas.drawLine(
(float) (viewWidth) / 6,
obtainSelectedAreaBorder()[1],
(float) (viewWidth * 5) / 6,
obtainSelectedAreaBorder()[1],
paint);
}
@Override
public void setAlpha(int alpha) {
}
@Override
public void setColorFilter(ColorFilter cf) {
}
@Override
public int getOpacity() {
return PixelFormat.UNKNOWN;
}
};
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);
}
/**
* 选中回调
*/
private void onSeletedCallBack() {
try {
if (onWheelViewListener != null) {
onWheelViewListener.onSelected(selectedIndex, items.get(selectedIndex));
}
} catch (Exception e) {
Log.e(TAG, "onSeletedCallBack 出错：" + e.getMessage(), e);
}
}
public void setSeletion(int position) {
final int p = position;
selectedIndex = p + offset;
this.post(() -> WheelView.this.smoothScrollTo(0, p * itemHeight));
}
@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 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();
}
}