标签：scoller
Scoller一般用在自定义View中
public class Scroller {
private int mStartX; //起始坐标点 , X轴方向
private int mStartY; //起始坐标点 , Y轴方向
private int mCurrX; //当前坐标点 X轴， 即调用startScroll函数后,经过一定时间所达到的值
private int mCurrY; //当前坐标点 Y轴， 即调用startScroll函数后,经过一定时间所达到的值
private float mDeltaX; //应该继续滑动的距离， X轴方向
private float mDeltaY; //应该继续滑动的距离， Y轴方向
private boolean mFinished; //是否已经完成本次滑动操作， 如果完成则为 true
//构造函数
public Scroller(Context context) {
this(context, null);
}
public final boolean isFinished() {
return mFinished;
}
//强制结束本次滑屏操作
public final void forceFinished(boolean finished) {
mFinished = finished;
}
public final int getCurrX() {
return mCurrX;
}
/* Call this when you want to know the new location. If it returns true,
* the animation is not yet finished. loc will be altered to provide the
* new location. */
//根据当前已经消逝的时间计算当前的坐标点，保存在mCurrX和mCurrY值中
public boolean computeScrollOffset() {
if (mFinished) { //已经完成了本次动画控制，直接返回为false
return false;
}
int timePassed = (int)(AnimationUtils.currentAnimationTimeMillis() - mStartTime);
if (timePassed < mDuration) {
switch (mMode) {
case SCROLL_MODE:
float x = (float)timePassed * mDurationReciprocal;
...
mCurrX = mStartX + Math.round(x * mDeltaX);
mCurrY = mStartY + Math.round(x * mDeltaY);
break;
...
}
else {
mCurrX = mFinalX;
mCurrY = mFinalY;
mFinished = true;
}
return true;
}
//开始一个动画控制，由(startX , startY)在duration时间内前进(dx,dy)个单位，即到达坐标为(startX+dx , startY+dy)出
public void startScroll(int startX, int startY, int dx, int dy, int duration) {
mFinished = false;
mDuration = duration;
mStartTime = AnimationUtils.currentAnimationTimeMillis();
mStartX = startX; mStartY = startY;
mFinalX = startX + dx; mFinalY = startY + dy;
mDeltaX = dx; mDeltaY = dy;
...
}
}
一些方法介绍
mScroller.getCurrX() //获取mScroller当前水平滚动的位置 mScroller.getCurrY() //获取mScroller当前竖直滚动的位置 mScroller.getFinalX() //获取mScroller最终停止的水平位置 mScroller.getFinalY() //获取mScroller最终停止的竖直位置 mScroller.setFinalX(int newX) //设置mScroller最终停留的水平位置，没有动画效果，直接跳到目标位置 mScroller.setFinalY(int newY) //设置mScroller最终停留的竖直位置，没有动画效果，直接跳到目标位置 //滚动，startX, startY为开始滚动的位置，dx,dy为滚动的偏移量, duration为完成滚动的时间 mScroller.startScroll(int startX, int startY, int dx, int dy) //使用默认完成时间250ms mScroller.startScroll(int startX, int startY, int dx, int dy, int duration) mScroller.computeScrollOffset() //返回值为boolean，true说明滚动尚未完成，false说明滚动已经完成。这是一个很重要的方法，通常放在View.computeScroll()中，用来判断是否滚动是否结束。
public class CustomView extends RelativeLayout {
private static final String TAG = "CustomView";
private Scroller mScroller;
private GestureDetector mGestureDetector;
public boolean flag = true;
public StateListener stateListener;
public CustomView(Context context) {
this(context, null);
}
public CustomView(Context context, AttributeSet attrs) {
super(context, attrs);
setClickable(true);
setLongClickable(true);
mScroller = new Scroller(context);
mGestureDetector = new GestureDetector(context, new CustomGestureListener());
}
public interface StateListener
{
public void changeText();
public void recoverText();
}
public void setStateListener(StateListener statelistener)
{
this.stateListener = statelistener;
}
//调用此方法滚动到目标位置
public void smoothScrollTo(int fx, int fy) {
int dx = fx - mScroller.getFinalX();
int dy = fy - mScroller.getFinalY();
smoothScrollBy(dx, dy);
}
//调用此方法设置滚动的相对偏移
public void smoothScrollBy(int dx, int dy) {
//设置mScroller的滚动偏移量
mScroller.startScroll(mScroller.getFinalX(), mScroller.getFinalY(), dx, dy);
invalidate();//这里必须调用invalidate()才能保证computeScroll()会被调用，否则不一定会刷新界面，看不到滚动效果
}
//在绘制View时，会在draw()过程调用该方法。
@Override
public void computeScroll() {
//先判断mScroller滚动是否完成
if (mScroller.computeScrollOffset()) {
//这里调用View的scrollTo()完成实际的滚动
scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
//必须调用该方法，否则不一定能看到滚动效果
postInvalidate();
}
super.computeScroll();
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_UP :
Log.i(TAG, "get Sy" + getScrollY());
System.out.println(getScrollX()+"x--"+getScrollY()+"y");
smoothScrollTo(0, 0);
System.out.println("up");
break;
default:
int distance = getScrollY();
System.out.println("distance"+distance);
if(distance <= 0)
{
flag = true;
if(distance > -200)
{
stateListener.recoverText();
}
else if(distance < -200)
{
stateListener.changeText();
}
return mGestureDetector.onTouchEvent(event);
}else
{
flag = false;
return false;
}
}
return super.onTouchEvent(event);
}
class CustomGestureListener implements GestureDetector.OnGestureListener {
@Override
public boolean onDown(MotionEvent e) {
// TODO Auto-generated method stub
return true;
}
@Override
public void onShowPress(MotionEvent e) {
// TODO Auto-generated method stub
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
// TODO Auto-generated method stub
return false;
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2,
float distanceX, float distanceY) {
if(flag)
{int dis = (int)((distanceY-0.5)/4);
Log.i(TAG, dis + ".");
smoothScrollBy(0, dis);}
return false;
}
@Override
public void onLongPress(MotionEvent e) {
// TODO Auto-generated method stub
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY) {
// TODO Auto-generated method stub
e1.getY();
e2.getY();
System.out.println(e1.getY()+"------"+e2.getY());
return false;
}
}
}标签：scoller
原文地址：http://blog.csdn.net/zxc123e/article/details/42126153
