我有一个自定义视图组和自定义的imageViews。使用它我可以用一个手势从一个图像视图滑动到另一个图像视图。
使用缩放缩放缩放ImageView时，视图组中无法使用缩放的某些方式，但根据缩放的空间。
enter code here
public class RealViewSwitcher extends ViewGroup {
public static boolean isAllowedToDispatchTouchEvents=false;
// TODO: This class does the basic stuff right now, but it would be cool to have certain things implemented,
// e.g. using an adapter for getting views instead of setting them directly, memory management and the
// possibility of scrolling vertically instead of horizontally. If you have ideas or patches, please visit
// my website and drop me a mail. :-)
/**
* Listener for the event that the RealViewSwitcher switches to a new view.
*/
public static interface OnScreenSwitchListener {
/**
* Notifies listeners about the new screen. Runs after the animation completed.
*
* @param screen The new screen index.
*/
void onScreenSwitched(int screen);
}
private static final int SNAP_VELOCITY = 1000;
private static final int INVALID_SCREEN = -1;
private Scroller mScroller;
private VelocityTracker mVelocityTracker;
private final static int TOUCH_STATE_REST = 0;
private final static int TOUCH_STATE_SCROLLING = 1;
private int mTouchState = TOUCH_STATE_REST;
private float mLastMotionX;
private int mTouchSlop;
private int mMaximumVelocity;
private int mCurrentScreen;
private int mNextScreen = INVALID_SCREEN;
private boolean mFirstLayout = true;
private OnScreenSwitchListener mOnScreenSwitchListener;
public RealViewSwitcher(Context context) {
super(context);
init();
}
public RealViewSwitcher(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
private void init() {
System.out.println("int()");
mScroller = new Scroller(getContext());
final ViewConfiguration configuration = ViewConfiguration.get(getContext());
mTouchSlop = configuration.getScaledTouchSlop();
mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
System.out.println("measured");
final int width = MeasureSpec.getSize(widthMeasureSpec);
final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
if (widthMode != MeasureSpec.EXACTLY) {
throw new IllegalStateException("ViewSwitcher can only be used in EXACTLY mode.");
}
final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
if (heightMode != MeasureSpec.EXACTLY) {
throw new IllegalStateException("ViewSwitcher can only be used in EXACTLY mode.");
}
// The children are given the same width and height as the workspace
final int count = getChildCount();
for (int i = 0; i < count; i++) {
getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
}
if (mFirstLayout) {
scrollTo(mCurrentScreen * width, 0);
mFirstLayout = false;
}
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int childLeft = 0;
System.out.println("Layout set");
final int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != View.GONE) {
final int childWidth = child.getMeasuredWidth();
child.layout(childLeft, 0, childLeft + childWidth, child.getMeasuredHeight());
childLeft += childWidth;
}
}
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
Log.d("TouchEvent", "parent:motion event detected");
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(ev);
final int action = ev.getAction();
final float x = ev.getX();
switch (action) {
case MotionEvent.ACTION_DOWN:
Log.d("TouchEvent", "parent:motion event to down");
/*
* If being flinged and user touches, stop the fling. isFinished will be false if being flinged.
*/
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
// Remember where the motion event started
mLastMotionX = x;
mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING;
break;
case MotionEvent.ACTION_MOVE:
Log.d("TouchEvent", "parent:motion event to move");
final int xDiff = (int) Math.abs(x - mLastMotionX);
boolean xMoved = xDiff > mTouchSlop;
if (xMoved) {
// Scroll if the user moved far enough along the X axis
mTouchState = TOUCH_STATE_SCROLLING;
}
if (mTouchState == TOUCH_STATE_SCROLLING) {
// Scroll to follow the motion event
final int deltaX = (int) (mLastMotionX - x);
mLastMotionX = x;
final int scrollX = getScrollX();
if (deltaX < 0) {
if (scrollX > 0) {
scrollBy(Math.max(-scrollX, deltaX), 0);
}
} else if (deltaX > 0) {
final int availableToScroll = getChildAt(getChildCount() - 1).getRight() - scrollX - getWidth();
if (availableToScroll > 0) {
scrollBy(Math.min(availableToScroll, deltaX), 0);
}
}
}
break;
case MotionEvent.ACTION_UP:
Log.d("TouchEvent", "parent:motion event to up");
if (mTouchState == TOUCH_STATE_SCROLLING) {
final VelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
int velocityX = (int) velocityTracker.getXVelocity();
if (velocityX > SNAP_VELOCITY && mCurrentScreen > 0) {
// Fling hard enough to move left
snapToScreen(mCurrentScreen - 1);
} else if (velocityX < -SNAP_VELOCITY && mCurrentScreen < getChildCount() - 1) {
// Fling hard enough to move right
snapToScreen(mCurrentScreen + 1);
} else {
snapToDestination();
}
if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
}
mTouchState = TOUCH_STATE_REST;
break;
case MotionEvent.ACTION_CANCEL:
Log.d("TouchEvent", "parent:motion event to cancel");
mTouchState = TOUCH_STATE_REST;
}
return true;
}
private void snapToDestination() {
final int screenWidth = getWidth();
final int whichScreen = (getScrollX() + (screenWidth / 2)) / screenWidth;
snapToScreen(whichScreen);
}
private void snapToScreen(int whichScreen) {
if (!mScroller.isFinished())
return;
whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1));
mNextScreen = whichScreen;
final int newX = whichScreen * getWidth();
final int delta = newX - getScrollX();
mScroller.startScroll(getScrollX(), 0, delta, 0, Math.abs(delta) * 2);
invalidate();
}
@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
postInvalidate();
} else if (mNextScreen != INVALID_SCREEN) {
mCurrentScreen = Math.max(0, Math.min(mNextScreen, getChildCount() - 1));
// notify observer about screen change
if (mOnScreenSwitchListener != null)
mOnScreenSwitchListener.onScreenSwitched(mCurrentScreen);
Log.d("TouchEvent", "parent:motion event to Compute scroll");
mNextScreen = INVALID_SCREEN;
}
}
/**
* Returns the index of the currently displayed screen.
*
* @return The index of the currently displayed screen.
*/
public int getCurrentScreen() {
return mCurrentScreen;
}
/**
* Sets the current screen.
*
* @param currentScreen The new screen.
*/
public void setCurrentScreen(int currentScreen) {
mCurrentScreen = Math.max(0, Math.min(currentScreen, getChildCount() - 1));
scrollTo(mCurrentScreen * getWidth(), 0);
invalidate();
}
/**
* Sets the {@link ViewSwitcher.OnScreenSwitchListener}.
*
* @param onScreenSwitchListener The listener for switch events.
*/
public void setOnScreenSwitchListener(OnScreenSwitchListener onScreenSwitchListener) {
mOnScreenSwitchListener = onScreenSwitchListener;
}
/* (non-Javadoc)
* @see android.view.ViewGroup#onInterceptTouchEvent(android.view.MotionEvent)
*/
public boolean onInterceptTouchEvent(MotionEvent ev)
{
Log.d("TouchEvent", "parent:Intercept Touch Event");
if(isAllowedToDispatchTouchEvents)
{
}onTouchEvent(ev);
return isAllowedToDispatchTouchEvents;
}
}