package com.ttj.view;
import java.lang.ref.WeakReference;
import java.lang.reflect.Field;
import android.content.Context;
import android.os.Handler;
import android.os.Message;
import android.support.v4.view.MotionEventCompat;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.animation.Interpolator;
/**
* Auto Scroll View Pager
* <ul>
* <strong>Basic Setting and Usage</strong>
* <li>{@link #startAutoScroll()} start auto scroll, or {@link #startAutoScroll(int)} start auto scroll delayed</li>
* <li>{@link #stopAutoScroll()} stop auto scroll</li>
* <li>{@link #setInterval(long)} set auto scroll time in milliseconds, default is {@link #DEFAULT_INTERVAL}</li>
* </ul>
* <ul>
* <strong>Advanced Settings and Usage</strong>
* <li>{@link #setDirection(int)} set auto scroll direction</li>
* <li>{@link #setCycle(boolean)} set whether automatic cycle when auto scroll reaching the last or first item, default
* is true</li>
* <li>{@link #setSlideBorderMode(int)} set how to process when sliding at the last or first item</li>
* <li>{@link #setStopScrollWhenTouch(boolean)} set whether stop auto scroll when touching, default is true</li>
* </ul>
*
* @author <a href="http://www.trinea.cn" target="_blank">Trinea</a> 2013-12-30
*/
public class AutoScrollViewPager extends ViewPager {
public static final int DEFAULT_INTERVAL = 1500;
public static final int LEFT = 0;
public static final int RIGHT = 1;
/** do nothing when sliding at the last or first item **/
public static final int SLIDE_BORDER_MODE_NONE = 0;
/** cycle when sliding at the last or first item **/
public static final int SLIDE_BORDER_MODE_CYCLE = 1;
/** deliver event to parent when sliding at the last or first item **/
public static final int SLIDE_BORDER_MODE_TO_PARENT = 2;
/** auto scroll time in milliseconds, default is {@link #DEFAULT_INTERVAL} **/
private long interval = DEFAULT_INTERVAL;
/** auto scroll direction, default is {@link #RIGHT} **/
private int direction = RIGHT;
/** whether automatic cycle when auto scroll reaching the last or first item, default is true **/
private boolean isCycle = true;
/** whether stop auto scroll when touching, default is true **/
private boolean stopScrollWhenTouch = true;
/** how to process when sliding at the last or first item, default is {@link #SLIDE_BORDER_MODE_NONE} **/
private int slideBorderMode = SLIDE_BORDER_MODE_NONE;
/** whether animating when auto scroll at the last or first item **/
private boolean isBorderAnimation = true;
/** scroll factor for auto scroll animation, default is 1.0 **/
private double autoScrollFactor = 1.0;
/** scroll factor for swipe scroll animation, default is 1.0 **/
private double swipeScrollFactor = 1.0;
private Handler handler;
private boolean isAutoScroll = false;
private boolean isStopByTouch = false;
private float touchX = 0f, downX = 0f;
private CustomDurationScroller scroller = null;
public static final int SCROLL_WHAT = 0;
public AutoScrollViewPager(Context paramContext) {
super(paramContext);
init();
}
public AutoScrollViewPager(Context paramContext, AttributeSet paramAttributeSet) {
super(paramContext, paramAttributeSet);
init();
}
private void init() {
handler = new MyHandler(this);
setViewPagerScroller();
}
/**
* start auto scroll, first scroll delay time is {@link #getInterval()}
*/
public void startAutoScroll() {
isAutoScroll = true;
sendScrollMessage((long)(interval + scroller.getDuration() / autoScrollFactor * swipeScrollFactor));
}
/**
* start auto scroll
*
* @param delayTimeInMills first scroll delay time
*/
public void startAutoScroll(int delayTimeInMills) {
isAutoScroll = true;
sendScrollMessage(delayTimeInMills);
}
/**
* stop auto scroll
*/
public void stopAutoScroll() {
isAutoScroll = false;
handler.removeMessages(SCROLL_WHAT);
}
/**
* set the factor by which the duration of sliding animation will change while swiping
*/
public void setSwipeScrollDurationFactor(double scrollFactor) {
swipeScrollFactor = scrollFactor;
}
/**
* set the factor by which the duration of sliding animation will change while auto scrolling
*/
public void setAutoScrollDurationFactor(double scrollFactor) {
autoScrollFactor = scrollFactor;
}
private void sendScrollMessage(long delayTimeInMills) {
/** remove messages before, keeps one message is running at most **/
handler.removeMessages(SCROLL_WHAT);
handler.sendEmptyMessageDelayed(SCROLL_WHAT, delayTimeInMills);
}
/**
* set ViewPager scroller to change animation duration when sliding
*/
private void setViewPagerScroller() {
try {
Field scrollerField = ViewPager.class.getDeclaredField("mScroller");
scrollerField.setAccessible(true);
Field interpolatorField = ViewPager.class.getDeclaredField("sInterpolator");
interpolatorField.setAccessible(true);
scroller = new CustomDurationScroller(getContext(), (Interpolator)interpolatorField.get(null));
scrollerField.set(this, scroller);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* scroll only once
*/
public void scrollOnce() {
PagerAdapter adapter = getAdapter();
int currentItem = getCurrentItem();
int totalCount;
if (adapter == null || (totalCount = adapter.getCount()) <= 1) {
return;
}
int nextItem = (direction == LEFT) ? --currentItem : ++currentItem;
if (nextItem < 0) {
if (isCycle) {
setCurrentItem(totalCount - 1, isBorderAnimation);
}
} else if (nextItem == totalCount) {
if (isCycle) {
setCurrentItem(0, isBorderAnimation);
}
} else {
setCurrentItem(nextItem, true);
}
}
/**
* <ul>
* if stopScrollWhenTouch is true
* <li>if event is down, stop auto scroll.</li>
* <li>if event is up, start auto scroll again.</li>
* </ul>
*/
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
int action = MotionEventCompat.getActionMasked(ev);
if (stopScrollWhenTouch) {
if ((action == MotionEvent.ACTION_DOWN) && isAutoScroll) {
isStopByTouch = true;
stopAutoScroll();
} else if (ev.getAction() == MotionEvent.ACTION_UP && isStopByTouch) {
startAutoScroll();
}
}
if (slideBorderMode == SLIDE_BORDER_MODE_TO_PARENT || slideBorderMode == SLIDE_BORDER_MODE_CYCLE) {
touchX = ev.getX();
if (ev.getAction() == MotionEvent.ACTION_DOWN) {
downX = touchX;
}
int currentItem = getCurrentItem();
PagerAdapter adapter = getAdapter();
int pageCount = adapter == null ? 0 : adapter.getCount();
/**
* current index is first one and slide to right or current index is last one and slide to left.<br/>
* if slide border mode is to parent, then requestDisallowInterceptTouchEvent false.<br/>
* else scroll to last one when current item is first one, scroll to first one when current item is last
* one.
*/
if ((currentItem == 0 && downX <= touchX) || (currentItem == pageCount - 1 && downX >= touchX)) {
if (slideBorderMode == SLIDE_BORDER_MODE_TO_PARENT) {
getParent().requestDisallowInterceptTouchEvent(false);
} else {
if (pageCount > 1) {
setCurrentItem(pageCount - currentItem - 1, isBorderAnimation);
}
getParent().requestDisallowInterceptTouchEvent(true);
}
return super.dispatchTouchEvent(ev);
}
}
getParent().requestDisallowInterceptTouchEvent(true);
return super.dispatchTouchEvent(ev);
}
private static class MyHandler extends Handler {
private final WeakReference<AutoScrollViewPager> autoScrollViewPager;
public MyHandler(AutoScrollViewPager autoScrollViewPager) {
this.autoScrollViewPager = new WeakReference<AutoScrollViewPager>(autoScrollViewPager);
}
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what) {
case SCROLL_WHAT:
AutoScrollViewPager pager = this.autoScrollViewPager.get();
if (pager != null) {
pager.scroller.setScrollDurationFactor(pager.autoScrollFactor);
pager.scrollOnce();
pager.scroller.setScrollDurationFactor(pager.swipeScrollFactor);
pager.sendScrollMessage(pager.interval + pager.scroller.getDuration());
}
default:
break;
}
}
}
/**
* get auto scroll time in milliseconds, default is {@link #DEFAULT_INTERVAL}
*
* @return the interval
*/
public long getInterval() {
return interval;
}
/**
* set auto scroll time in milliseconds, default is {@link #DEFAULT_INTERVAL}
*
* @param interval the interval to set
*/
public void setInterval(long interval) {
this.interval = interval;
}
/**
* get auto scroll direction
*
* @return {@link #LEFT} or {@link #RIGHT}, default is {@link #RIGHT}
*/
public int getDirection() {
return (direction == LEFT) ? LEFT : RIGHT;
}
/**
* set auto scroll direction
*
* @param direction {@link #LEFT} or {@link #RIGHT}, default is {@link #RIGHT}
*/
public void setDirection(int direction) {
this.direction = direction;
}
/**
* whether automatic cycle when auto scroll reaching the last or first item, default is true
*
* @return the isCycle
*/
public boolean isCycle() {
return isCycle;
}
/**
* set whether automatic cycle when auto scroll reaching the last or first item, default is true
*
* @param isCycle the isCycle to set
*/
public void setCycle(boolean isCycle) {
this.isCycle = isCycle;
}
/**
* whether stop auto scroll when touching, default is true
*
* @return the stopScrollWhenTouch
*/
public boolean isStopScrollWhenTouch() {
return stopScrollWhenTouch;
}
/**
* set whether stop auto scroll when touching, default is true
*
* @param stopScrollWhenTouch
*/
public void setStopScrollWhenTouch(boolean stopScrollWhenTouch) {
this.stopScrollWhenTouch = stopScrollWhenTouch;
}
/**
* get how to process when sliding at the last or first item
*
* @return the slideBorderMode {@link #SLIDE_BORDER_MODE_NONE}, {@link #SLIDE_BORDER_MODE_TO_PARENT},
* {@link #SLIDE_BORDER_MODE_CYCLE}, default is {@link #SLIDE_BORDER_MODE_NONE}
*/
public int getSlideBorderMode() {
return slideBorderMode;
}
/**
* set how to process when sliding at the last or first item
*
* @param slideBorderMode {@link #SLIDE_BORDER_MODE_NONE}, {@link #SLIDE_BORDER_MODE_TO_PARENT},
* {@link #SLIDE_BORDER_MODE_CYCLE}, default is {@link #SLIDE_BORDER_MODE_NONE}
*/
public void setSlideBorderMode(int slideBorderMode) {
this.slideBorderMode = slideBorderMode;
}
/**
* whether animating when auto scroll at the last or first item, default is true
*
* @return
*/
public boolean isBorderAnimation() {
return isBorderAnimation;
}
/**
* set whether animating when auto scroll at the last or first item, default is true
*
* @param isBorderAnimation
*/
public void setBorderAnimation(boolean isBorderAnimation) {
this.isBorderAnimation = isBorderAnimation;
}
}