支持无限循环，自动轮播，反转播放的ViewPagerAdapter
触摸暂停切换
缩放pagertransformer
无限循环是利用反射设置一个很大的数值来无限循环
效果
GIF.gif
github地址
GIF.gif
使用
LoopFragmentPagerAdapter adapter = new LoopFragmentPagerAdapter(getSupportFragmentManager()) {
@Override
public int getActualCount() {
return 3;
}
@Override
public Fragment getActualItem(int position) {
return new MyFragment();
}
@Override
public CharSequence getActualPagerTitle(int position) {
return "标题" + position;
}
};
adapter.setSwitchPeriod(5000);
//不循环 反转轮播
adapter.setLoop(false);
//自动轮播
adapter.setAutoSwitch(true);
viewPager.setAdapter(adapter);
代码
/**
* Created by 不听话的好孩子 on 2017/12/6.
* <p>
* 有RXjava用Rxjava实现切换，无Rxjava用post
*/
public abstract class LoopFragmentPagerAdapter extends FragmentStatePagerAdapter {
/**
* 用来启动动画 设置循环
*/
private boolean isfirst = true;
/**
* 触摸的时候停止切换
*/
private boolean touched = false;
/**
* 切换间隔
*/
private int switchPeriod = 5000;
/**
* 自动切换
*/
private boolean autoSwitch = true;
/**
* 是否需要无限循环
*/
private boolean loop = true;
/**
* post runnable
*/
private Runnable action;
private int BIGCOUNT = 1000000;
private Disposable disposable;
private boolean reverse;
/**
* 有无rxjava
*/
private boolean hasRx;
public LoopFragmentPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return getActualItem(position % getActualCount());
}
@Override
public void startUpdate(final ViewGroup container) {
super.startUpdate(container);
if (isfirst) {
isfirst = false;
if (loop) {
try {
doSettCurrenPager(container);
} catch (Exception e) {
e.printStackTrace();
}
}
if (autoSwitch) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
startLoop((ViewPager) container);
}
}
}
}
/**
* 反射设置一个很大的位置达到伪无限循环
*
* @param container
* @throws Exception
*/
private void doSettCurrenPager(ViewGroup container) throws Exception {
Field mCurItem = ViewPager.class.getDeclaredField("mCurItem");
mCurItem.setAccessible(true);
mCurItem.setInt(container, 1000000 - (BIGCOUNT % getActualCount()));
}
@Override
public CharSequence getPageTitle(int position) {
return getActualPagerTitle(position % getActualCount());
}
@Override
public int getCount() {
return loop ? Integer.MAX_VALUE : getActualCount();
}
/**
* 执行循环切换
*
* @param viewPager
*/
@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR2)
private void startLoop(final ViewPager viewPager) {
hasRx = checkIfHasRx();
Log.w("LoopFragmentPager", "startLoop: " + (hasRx ? "当前使用Rxjava" : "当前使用View.post"), null);
if (!hasRx) {
usePost(viewPager);
} else {
userRx(viewPager);
}
viewPager.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_MOVE:
if (!touched) {
touched = true;
if (!hasRx) {
viewPager.removeCallbacks(action);
}
}
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
touched = false;
if (!hasRx) {
viewPager.postDelayed(action, switchPeriod);
}
break;
}
return false;
}
});
viewPager.getViewTreeObserver().addOnWindowAttachListener(new ViewTreeObserver.OnWindowAttachListener() {
@Override
public void onWindowAttached() {
}
@Override
public void onWindowDetached() {
disposable.dispose();
viewPager.removeCallbacks(action);
action = null;
viewPager.getViewTreeObserver().removeOnWindowAttachListener(this);
viewPager.setOnTouchListener(null);
}
});
}
/**
* 用Rxjava做循环切换
*
* @param viewPager
*/
private void userRx(final ViewPager viewPager) {
disposable = Observable.interval(switchPeriod, switchPeriod, TimeUnit.MILLISECONDS)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer<Long>() {
@Override
public void accept(Long aLong) throws Exception {
if (!touched) {
viewPager.setCurrentItem(caculatItem(viewPager));
}
}
});
}
/**
* 用View.post作循环切换
*
* @param container
*/
@SuppressLint("ClickableViewAccessibility")
private void usePost(final ViewPager container) {
if (action == null) {
action = new Runnable() {
@Override
public void run() {
container.setCurrentItem(caculatItem(container));
container.postDelayed(this, switchPeriod);
}
};
}
container.postDelayed(action, switchPeriod);
}
private int caculatItem(ViewPager viewPager){
int nextItem = !reverse ? (viewPager.getCurrentItem() + 1) : (viewPager.getCurrentItem() - 1);
if (!loop) {
if (nextItem >= getActualCount()) {
reverse = true;
nextItem = viewPager.getCurrentItem() - 1;
}
if (nextItem < 0) {
reverse = false;
nextItem = 1;
}
}
return nextItem;
}
/**
* 是否含有Rxjava库
*
* @return
*/
private boolean checkIfHasRx() {
try {
Class.forName("io.reactivex.android.schedulers.AndroidSchedulers");
} catch (ClassNotFoundException e) {
e.printStackTrace();
return false;
}
return true;
}
public abstract int getActualCount();
public abstract Fragment getActualItem(int position);
public abstract CharSequence getActualPagerTitle(int position);
}
