首先来看下实现的最终效果：
1.每隔3秒自动轮播；
2.手指滑动时取消自动轮播；
3.轮播动画的自定义。
本文主要参考：https://www.cnblogs.com/Oueen/p/5338164.html
https://www.jianshu.com/p/c904f4c33e9f
需要重写transformPage方法:
import android.content.Context;
import android.support.v4.view.ViewPager;
import android.view.View;
import com.cleanmaster.security.util.DimenUtils;
/**
* 实现ViewPager左右滑动时的时差
* Created by xmuSistone on 2016/9/18.
*/
public class CustPagerTransformer implements ViewPager.PageTransformer {
private int maxTranslateOffsetX;
private ViewPager viewPager;
private int mWidth = DimenUtils.getScreenWidth();
public CustPagerTransformer(Context context) {
this.maxTranslateOffsetX = DimenUtils.dp2px((float) (mWidth * 0.07)); //改变两边小卡片 到 中间卡片的 距离 ,此处动态改变宽度
}
public void transformPage(View view, float position) {
if (viewPager == null) {
viewPager = (ViewPager) view.getParent();
}
int leftInScreen = view.getLeft() - viewPager.getScrollX();
int centerXInViewPager = leftInScreen + view.getMeasuredWidth() / 2;
int offsetX = centerXInViewPager - viewPager.getMeasuredWidth() / 2;
float offsetRate = (float) offsetX * 0.3f / viewPager.getMeasuredWidth(); //改变两边小卡片动画缩放程度
float scaleFactor = 1 - Math.abs(offsetRate);
if (scaleFactor > 0) {
view.setScaleX(scaleFactor);
view.setScaleY(scaleFactor);
view.setTranslationX(-maxTranslateOffsetX * offsetRate);
}
}
}需要在viewPager的addOnPageChangeListener -- > onPageScrollStateChanged方法中监听：
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int i, float v, int i1) {
}
@Override
public void onPageSelected(int i) {
}
@Override
public void onPageScrollStateChanged(int state) {
if (state == ViewPager.SCROLL_STATE_DRAGGING) {
cancelAutoScroll();
} else if (state == ViewPager.SCROLL_STATE_SETTLING) {
cancelAutoScroll();
} else if (state == ViewPager.SCROLL_STATE_IDLE) {
startAutoScroll();
}
}
});下面贴上这个viewpager的所有代码：
mainactivity贴上后可以直接运行，
public class MainActivity extends AppCompatActivity {
private Context mContext;
private ViewPager mViewPager;
private int viewPagerItemSize = 0;
private final int INTERVAL = 1000 * 3;
private ArrayList mArrayList;
private final static int SET_VIEWPAGER_ITEM = 9527;
private LauncherViewPagerAdapter mViewPagerAdapter;
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what) {
case SET_VIEWPAGER_ITEM:
if (mViewPager != null && mViewPagerAdapter != null) {
int currentItemIndex = mViewPager.getCurrentItem();
int itemsCount = mViewPagerAdapter.getCount();
if ((currentItemIndex + 1) < itemsCount) {
mViewPager.setCurrentItem(currentItemIndex + 1, true);
} else {
mViewPager.setCurrentItem(0, false);
}
}
break;
}
}
};
private Runnable mRunnable = new Runnable() {
@Override
public void run() {
Message message = mHandler.obtainMessage();
message.what = SET_VIEWPAGER_ITEM;
mHandler.sendMessage(message);
mHandler.removeCallbacks(mRunnable);
mHandler.postDelayed(this, INTERVAL);
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//去掉状态栏
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);
init();
}
//初始化，此处需要确保先赋值，后加载数据，否则为空
private void init() {
initData();
if (viewPagerItemSize > 0) {
initViewPager();
setAutoChangeViewPager();
}
}
//准备ViewPager将显示的数据
private void initData() {
mContext = this;
mArrayList = new ArrayList();
mArrayList.add(R.drawable.a);
mArrayList.add(R.drawable.b);
mArrayList.add(R.drawable.c);
mArrayList.add(R.drawable.d);
viewPagerItemSize = mArrayList.size();
}
//初始化ViewPager
private void initViewPager() {
mViewPager = (ViewPager) findViewById(R.id.guide_viewpager);
mViewPagerAdapter = new LauncherViewPagerAdapter(mContext);
mViewPager.setPageTransformer(false, new CustPagerTransformer(this));
mViewPagerAdapter.setAdapterData(mArrayList);
mViewPager.setAdapter(mViewPagerAdapter);
int currentItem = Integer.MAX_VALUE / 2 - Integer.MAX_VALUE / 2 % viewPagerItemSize;
mViewPager.setCurrentItem(currentItem);
mViewPager.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View arg0, MotionEvent arg1) {
mViewPager.requestDisallowInterceptTouchEvent(true);
return false;
}
});
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int i, float v, int i1) {
}
@Override
public void onPageSelected(int i) {
}
@Override
public void onPageScrollStateChanged(int state) {
if (state == ViewPager.SCROLL_STATE_DRAGGING) {
cancelAutoScroll();
} else if (state == ViewPager.SCROLL_STATE_SETTLING) {
cancelAutoScroll();
} else if (state == ViewPager.SCROLL_STATE_IDLE) {
startAutoScroll();
}
}
});
}
private void startAutoScroll() {
cancelAutoScroll();
mHandler.postDelayed(mRunnable, 1000 * 3);
}
public void cancelAutoScroll() {
mHandler.removeCallbacksAndMessages(null);
}
//开启ViewPager的自动轮播
@SuppressWarnings("deprecation")
private void setAutoChangeViewPager() {
mHandler.postDelayed(mRunnable, INTERVAL);
}
@Override
protected void onDestroy() {
super.onDestroy();
if (null != mViewPager) {
mViewPager.removeAllViews();
mViewPager = null;
}
}
class LauncherViewPagerAdapter extends PagerAdapter {
private Context mContext;
private ArrayList pagesArrayList;
private View itemView;
public LauncherViewPagerAdapter(Context context) {
this.mContext = context;
}
public void setAdapterData(ArrayList arrayList) {
pagesArrayList = arrayList;
}
@Override
public int getCount() {
return Integer.MAX_VALUE;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
if (pagesArrayList.size() > 0) {
itemView = LayoutInflater.from(mContext).inflate(R.layout.guide_pager_adapter, null);
itemView.setFocusable(true);
ImageView imageView = (ImageView) itemView.findViewById(R.id.imageView);
imageView.setBackgroundResource(pagesArrayList.get(position % pagesArrayList.size()));
container.addView(itemView);
itemView.setClickable(true); //这里itemView需要设置，否则up事件无法响应
itemView.setEnabled(true);
itemView.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
mHandler.removeCallbacksAndMessages(null);
break;
case MotionEvent.ACTION_MOVE:
case MotionEvent.ACTION_UP:
mHandler.removeCallbacksAndMessages(null);
setAutoChangeViewPager();
break;
}
return false;
}
});
return itemView;
}
return null;
}
@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View) object);
}
}
}主布局文件：activity_main.xml:
viewpager的adapter文件：guide_pager_adapter.xml
其实也就是viewpager的简单用法，自己再找几张图片放到drawable下面就可以完美运行了，
在git上有完整的项目：
https://github.com/buder-cp/base_component_learn/tree/master/myviewpager
