我找到了一些人的代码，一个scrollLayout，它的视图组可以保存一些视图，你可以在其中滑动视图，如android的视图寻呼机。例如，如果我有3个意见。 V0，V1，V2。当我刷过scrollLayout时，它调用了onViewChange（View v），v就是你所看到的视图。但现在我想循环查看其中的视图，我该怎么做呢？我的要求是， 当我继续滑动它时，结果是，v0，v1，v2 v0，v1，v2，v0，v1，v2 ......
答案 0 :(得分：0)
public class ScrollLayout extends ViewGroup {
private static final String TAG = "ScrollLayout";
private Scroller mScroller;
private VelocityTracker mVelocityTracker;
private int mCurScreen;
private int mDefaultScreen = 0;
private static final int TOUCH_STATE_REST = 0;
private static final int TOUCH_STATE_SCROLLING = 1;
private static final int SNAP_VELOCITY = 9600;
private int mTouchState = TOUCH_STATE_REST;
private int mTouchSlop;
private float mLastMotionX;
private float mLastMotionY;
private OnViewChangeListener mOnViewChangeListener;
/**
* 设置是否可左右滑动
* @author liux
*/
private boolean isScroll = true;
public void setIsScroll(boolean b) {
this.isScroll = b;
}
public ScrollLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public ScrollLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
mScroller = new Scroller(context);
mCurScreen = mDefaultScreen;
mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int childLeft = 0;
final int childCount = getChildCount();
for (int i = 0; i < childCount; i++) {
final View childView = getChildAt(i);
if (childView.getVisibility() != View.GONE) {
final int childWidth = childView.getMeasuredWidth();
childView.layout(childLeft, 0, childLeft + childWidth,
childView.getMeasuredHeight());
childLeft += childWidth;
}
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
//Log.e(TAG, "onMeasure");
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
final int width = MeasureSpec.getSize(widthMeasureSpec);
final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
if (widthMode != MeasureSpec.EXACTLY) {
throw new IllegalStateException(
"ScrollLayout only canmCurScreen run at EXACTLY mode!");
}
final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
if (heightMode != MeasureSpec.EXACTLY) {
throw new IllegalStateException(
"ScrollLayout only can run at EXACTLY mode!");
}
// The children are given the same width and height as the scrollLayout
final int count = getChildCount();
for (int i = 0; i < count; i++) {
getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
}
// Log.e(TAG, "moving to screen "+mCurScreen);
scrollTo(mCurScreen * width, 0);
}
/**
* According to the position of current layout scroll to the destination
* page.
*/
public void snapToDestination() {
final int screenWidth = getWidth();
final int destScreen = (getScrollX() + screenWidth / 2) / screenWidth;
snapToScreen(destScreen);
}
public void snapToScreen(int whichScreen) {
//是否可滑动
if(!isScroll) {
this.setToScreen(whichScreen);
return;
}
scrollToScreen(whichScreen);
}
public void scrollToScreen(int whichScreen) {
// get the valid layout page
whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1));
if (getScrollX() != (whichScreen * getWidth())) {
final int delta = whichScreen * getWidth() - getScrollX();
mScroller.startScroll(getScrollX(), 0, delta, 0,
Math.abs(delta) * 1);//持续滚动时间 以毫秒为单位
mCurScreen = whichScreen;
invalidate(); // Redraw the layout
if (mOnViewChangeListener != null)
{
mOnViewChangeListener.OnViewChange(mCurScreen);
}
}
}
public void setToScreen(int whichScreen) {
whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1));
mCurScreen = whichScreen;
scrollTo(whichScreen * getWidth(), 0);
if (mOnViewChangeListener != null)
{
mOnViewChangeListener.OnViewChange(mCurScreen);
}
}
public int getCurScreen() {
return mCurScreen;
}
@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
postInvalidate();
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
//是否可滑动
if(!isScroll) {
return false;
}
Log.d("lightmanTouch", "Scroll onTouch "+event.getAction());
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(event);
final int action = event.getAction();
final float x = event.getX();
final float y = event.getY();
switch (action) {
case MotionEvent.ACTION_DOWN:
//Log.e(TAG, "event down!");
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
mLastMotionX = x;
//---------------New Code----------------------
mLastMotionY = y;
//---------------------------------------------
break;
case MotionEvent.ACTION_MOVE:
int deltaX = (int) (mLastMotionX - x);
//---------------New Code----------------------
int deltaY = (int) (mLastMotionY - y);
if(Math.abs(deltaX) < 200 && Math.abs(deltaY) > 50)
break;
mLastMotionY = y;
//-------------------------------------
mLastMotionX = x;
if(Math.abs(deltaX) > 10)
scrollBy(deltaX, 0);
Log.d("movescroll", "deltax = "+ deltaX);
break;
case MotionEvent.ACTION_UP:
//Log.e(TAG, "event : up");
// if (mTouchState == TOUCH_STATE_SCROLLING) {
final VelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000);
int velocityX = (int) velocityTracker.getXVelocity();
//Log.e(TAG, "velocityX:" + velocityX);
if (velocityX > SNAP_VELOCITY && mCurScreen > 0) {
// Fling enough to move left
//Log.e(TAG, "snap left");
snapToScreen(mCurScreen - 1);
} else if (velocityX < -SNAP_VELOCITY
&& mCurScreen < getChildCount() - 1) {
// Fling enough to move right
//Log.e(TAG, "snap right");
snapToScreen(mCurScreen + 1);
} else {
snapToDestination();
}
if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
// }
mTouchState = TOUCH_STATE_REST;
break;
case MotionEvent.ACTION_CANCEL:
mTouchState = TOUCH_STATE_REST;
break;
}
Log.d("SCROLLL", "before true "+System.currentTimeMillis());
return true;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
//Log.e(TAG, "onInterceptTouchEvent-slop:" + mTouchSlop);
final int action = ev.getAction();
if ((action == MotionEvent.ACTION_MOVE)
&& (mTouchState != TOUCH_STATE_REST)) {
if(isScroll)
return true;
else
return false;
}
final float x = ev.getX();
final float y = ev.getY();
switch (action) {
case MotionEvent.ACTION_MOVE:
final int xDiff = (int) Math.abs(mLastMotionX - x);
if (xDiff > mTouchSlop) {
mTouchState = TOUCH_STATE_SCROLLING;
}
break;
case MotionEvent.ACTION_DOWN:
mLastMotionX = x;
mLastMotionY = y;
mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST
: TOUCH_STATE_SCROLLING;
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
mTouchState = TOUCH_STATE_REST;
break;
}
if(isScroll)
return mTouchState != TOUCH_STATE_REST;
else
return false;
}
/**
* 设置屏幕切换监听器
* @param listener
*/
public void SetOnViewChangeListener(OnViewChangeListener listener)
{
mOnViewChangeListener = listener;
}
/**
* 屏幕切换监听器
* @author liux
*/
public interface OnViewChangeListener {
public void OnViewChange(int view);
}
@Override
protected void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
int scrollX = getScrollX();
final int N = getChildCount();
final int width = getWidth();
if (scrollX < 0) {
View lastChild = getChildAt(N - 1);
Log.d("TEST", "draw extra left ,scrollX is : " + scrollX + " width:"+lastChild.getWidth());
// end of first view and draw last view at its left
canvas.save();
canvas.translate(-width, 0);
canvas.clipRect(0, 0, width, getBottom());
lastChild.draw(canvas);
canvas.restore();
} else if (scrollX > (N - 1) * width) {
Log.d("TEST", "draw extra right ,scrollX is : " + scrollX);
View firstChild = getChildAt(0);
canvas.save();
canvas.translate(N * width, 0);
canvas.clipRect(0, 0, width, getBottom());
firstChild.draw(canvas);
canvas.restore();
}
}
}