最近很蛋疼，项目要模仿网易新闻的样式去做。上次把仿网易新闻客户端的下拉刷新写出来了，这次是ViewPager的滑动，同时ViewPager的上面标题下划线跟随者移动，本来通过ViewPager的OnPagerChangeListener的监听事件就可以完成，但是做出来之后，因为需要一直的刷新，所以很卡，一气之下，呵呵，自己完全的画了。整个点击事件，滑动事件都自己处理了。
public class ColumnHorizontalScrollView extends View implements OnPageChangeListener {
private Context context;
private int width ;
private int padingLeft;
private int padingRight ;
private float lineStartX = 0 ;
private float lineEndX = 0 ;
private Paint textPaint;
private int textWidth ;
private int lastPosition = 0 ;
private float lineScale = 0 ;
private ViewPager mViewPager ;
/**
* 这些事默认设置的
*/
private static final int DEFULT_TEXT_COLOR = Color.BLACK;
private static final int DEFULT_TEXT_SIZE = 40;
private static final int DEFULT_LINE_COLOR = Color.RED;
private static final int DEFULT_LINE_STRO = 5;
private String [] str ; // 存储 题要显示的字符
private float [] strX ; // 存储 每个字符 开始的X位置
private float [] strWidth ; // 存储每个字符的长度
private int startX; // 与手势相关 记录按下的X的坐标
private int recordDownX = 0 ;
private OnClickOneListener mOnClickOneListener ;
private OverScroller mScroller;
public ColumnHorizontalScrollView(Context context, AttributeSet attrs,
int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context);
}
public ColumnHorizontalScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public ColumnHorizontalScrollView(Context context) {
super(context);
init(context);
}
/**
* 初始化的时候需要new出来的一些类，和必要的设置
* @param context
*/
private void init(Context context){
this.context = context ;
mScroller = new OverScroller(context,new LinearInterpolator());
textPaint = new Paint();
linePaint = new Paint();
textPaint.setColor(DEFULT_TEXT_COLOR);
textPaint.setTextSize(DEFULT_TEXT_SIZE);
textPaint.setTypeface(Typeface.SANS_SERIF);
linePaint.setColor(DEFULT_LINE_COLOR);
linePaint.setStrokeWidth(DEFULT_LINE_STRO);
}
/**
* 画图
*/
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (str == null) {
return ;
}
measureSize();
drawText(canvas); //画字
measureLineSize();//测量下划线的位置
drawLine(canvas);//画下划线
}
/**
* 这个是用来通过Scroller来控制缓冲变化的 后来不需要了
*/
@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
}
super.computeScroll();
postInvalidate();
}
/**
* 画字的具体代码
* @param canvas
*/
private void drawText(Canvas canvas){
int totel = 0 ;
for (int i = 0; i < str.length; i++) {
if (i == 0 ) {
totel += padingLeft;
}
strX[i] = totel ;
canvas.drawText(str[i], strX[i], textHeight, textPaint);
float oneTextWidth = textPaint.measureText(str[i]);
totel =(int) (totel + oneTextWidth +space);
strWidth[i] = oneTextWidth ;
}
textWidth = totel - space +padingLeft ;
}
private void drawLine(Canvas canvas){
canvas.drawLine(lineStartX, lineHeight ,lineEndX , lineHeight, linePaint);
}
private void measureSize(){
width = getWidth();
height = getHeight();
padingLeft = getPaddingLeft();
padingRight = getPaddingRight();
textHeight = (int) (height / 2 - (textPaint.descent() + textPaint.ascent())/2);
lineHeight = (int) (textHeight - (textPaint.descent() + textPaint.ascent()));
}
private void measureLineSize(){
lineStartX = strX[lastPosition] - space / 2 + (strWidth[lastPosition] + space )* lineScale;
if ((lastPosition + 1) == mViewPager.getAdapter().getCount()) {
lineEndX = strX[lastPosition] + strWidth[lastPosition] + space / 2 ;
}else {
lineEndX = strX[lastPosition] + strWidth[lastPosition] + space / 2 + ( strWidth[lastPosition + 1] + space ) * lineScale;
}
}
public void setTitle(String ...str){
this.str = str ;
strX = new float[str.length];
strWidth = new float[str.length];
}
private int space = 0 ;
private Paint linePaint;
private int lineHeight;
private int height;
private int textHeight;
public void setspace(int space){
this.space = space ;
}
public void setTextColorResourceId(int colorid){
int color = context.getResources().getColor(colorid);
textPaint.setColor(color);
}
public void setTextColor(int color){
textPaint.setColor(color);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
startX = recordDownX = (int) event.getX();
break;
case MotionEvent.ACTION_MOVE:
int moveX = (int) event.getX();
int scrollX = getScrollX();
if (Math.abs(moveX - recordDownX ) > 32 ) {
smootMove(scrollX , startX - moveX);
}
startX = (int) event.getX();
break;
case MotionEvent.ACTION_UP:
int upX = (int) event.getX();
if (Math.abs(upX - recordDownX ) < 32 ) {
int position = decidePosition(upX);
setPosition(position);
if (mOnClickOneListener != null) {
mOnClickOneListener.onClick(position) ;
}
}
break;
}
return true;
}
private int decidePosition(int upX){
for (int i = 0; i < strX.length; i++) {
if ((upX + getScrollX()) < (strX[i] + strWidth[i]) + space / 2) {
return i ;
}
}
return 0 ;
}
public void setPosition(int position){
// lastPosition = position ;
// int scrollX = getScrollX();
// int location = (int) (strX[lastPosition] - space - 20);
// int dy = (int)(location - getScrollX());
// if ((location + width) > (textWidth + padingRight ) ) {
// mScroller.startScroll(scrollX, 0,textWidth + padingRight - width - getScrollX() , 0, 200);
// }else {
// mScroller.startScroll(scrollX, 0, dy , 0, 200);
// }
// if ((scrollX + dy ) > (textWidth+padingRight - width)) {
// mScroller.startScroll(scrollX, 0, textWidth+padingRight - width - scrollX , 0, 200);
// }else {
// mScroller.startScroll(scrollX, 0, dy , 0, 200);
// }
mViewPager.setCurrentItem(position);
}
private void smootMove(int scrollX , int dy){
if ((scrollX <= 0 && dy > 0 && textWidth > width) || (scrollX > 0)) {
if ((scrollX + dy) < 0 ) {
scrollTo(0 , 0);
}else {
if ((scrollX + dy + getWidth()) > (textWidth+padingRight )) {
scrollTo(textWidth +padingRight - getWidth() , 0);
}else {
scrollTo(scrollX + dy , 0);
}
}
}
}
public void setViewPager(ViewPager mViewPager){
this.mViewPager = mViewPager;
if (this.mViewPager != null) {
this.mViewPager.setOnPageChangeListener(this);
}
}
/**
* dip转为 px
*/
public int dip2px(float dipValue) {
final float scale = context.getResources().getDisplayMetrics().density;
return (int) (dipValue * scale + 0.5f);
}
@Override
public void onPageScrollStateChanged(int arg0) {
}
@Override
public void onPageScrolled(int lastPosition, float scale, int location) {
this.lastPosition = lastPosition ;
lineScale = scale ;
invalidate();
smootMove((int)(strX[lastPosition] - space - 20 ) ,(int)((strWidth[lastPosition] + space )* lineScale));
}
@Override
public void onPageSelected(int arg0) {
}
public void setOnClickOneListener (OnClickOneListener mOnClickOneListener){
this.mOnClickOneListener = mOnClickOneListener ;
}
/**
* 内部接口 是点击事件的接口
* @author lenovo
*
*/
interface OnClickOneListener{
public void onClick(int position);
}
}
