viewpage 循环滑动播放图片

Posted 2020-08-21 self-confidence,the source of

     一般来说，viewpage 只支持图片的顺序滑动播放，在滑到边界时就再也滑不动了，如果要想继续滑动，只能向两边额外增加一张相片，即把第一张相片的位置放在最后一张图片的后面，给用户的感觉我继续滑就滑到了第一张，也就有了循环滑动的效果，而我们只需要在内部对他实际滑动到的序号做相应处理就好了。原理图如下

github上的开源控件也实现了循环滑动，我还没下下来看，一并附上地址，有兴趣的朋友可以研究下，

https://github.com/imbryk/LoopingViewPager

直接看代码

1. activity代码, 这里只是简单的viewpage用法，没啥特殊之处，不做过多解析。

public class AppMaskActivity extends RoboActivity implements View.OnClickListener {
    public static final String HOME_MSG_CONTENT = "homemsg_content";

    //首页消息中心弹框提示
    @InjectView(R.id.rel_msg_popup_container)
    private RelativeLayout mRelMsgPopupContainer;
    @InjectView(R.id.vp_msg_img)
    private ViewPager mVpMsgImg;
    @InjectView(R.id.ll_dot_container)
    private LinearLayout mLlDotContainer;
    @InjectView(R.id.rel_vp_container)
    private RelativeLayout mRelVpContainer;
    @InjectView(R.id.iv_close)
    private ImageView mIvClose;

    private ArrayList<ImageView> pageViews;
    private ImagePagerAdapter msgImgAdapter;

    private Context context;
    private List<MessageInfo> homeMessageList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_app_mask);
        context = this;
        mRelMsgPopupContainer.setOnClickListener(this);
        mIvClose.setOnClickListener(this);

        //将view装入数组
        loadVpView();

        if (homeMessageList == null || homeMessageList.size() == 0){
            finish();
            return;
        }
        msgImgAdapter = new ImagePagerAdapter(this, pageViews, mVpMsgImg, mLlDotContainer, homeMessageList);
        mVpMsgImg.setPageMargin(120);
        mVpMsgImg.setPageTransformer(true, new ZoomOutPageTransformer());
        mVpMsgImg.setAdapter(msgImgAdapter);
        if (pageViews.size() > 1){
            mVpMsgImg.setCurrentItem(pageViews.size()/2);
        }
    }

    private void loadVpView() {
        homeMessageList = HomeMsgManager.getInstance().getHomeMsgs();
        pageViews = new ArrayList<ImageView>();
        for (int i = 0; i < homeMessageList.size(); i++) {
            ImageView iv = new ImageView(this);
            Drawable drawable = HomeMsgManager.getInstance().getLocalDrawable(context, homeMessageList.get(i).getPicUrl());
            if (drawable == null){
                continue;
            }
            iv.setImageDrawable(drawable);
            pageViews.add(iv);
        }
    }


    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.rel_msg_popup_container:
            case R.id.iv_close:
                finish();
                break;
        }
    }
}

zoomoutpageTransform.java 这里是页面滑动的效果

public class ZoomOutPageTransformer implements ViewPager.PageTransformer {
    private static final float MIN_SCALE = 0.85f;
    private static final float MIN_ALPHA = 0.5f;

    @SuppressLint("NewApi")
    public void transformPage(View view, float position) {
        int pageWidth = view.getWidth();
        int pageHeight = view.getHeight();

        Log.e("TAG", view + " , " + position + "");

        if (position < -1) { // [-Infinity,-1)
            // This page is way off-screen to the left.
            view.setAlpha(0);

        } else if (position <= 1) //a页滑动至b页 ； a页从 0.0 -1 ；b页从1 ~ 0.0
        { // [-1,1]
            // Modify the default slide transition to shrink the page as well
            float scaleFactor = Math.max(MIN_SCALE, 1 - Math.abs(position));
            float vertMargin = pageHeight * (1 - scaleFactor) / 2;
            float horzMargin = pageWidth * (1 - scaleFactor) / 2;
            if (position < 0) {
                view.setTranslationX(horzMargin - vertMargin / 2);
            } else {
                view.setTranslationX(-horzMargin + vertMargin / 2);
            }

            // Scale the page down (between MIN_SCALE and 1)
            view.setScaleX(scaleFactor);
            view.setScaleY(scaleFactor);

            // Fade the page relative to its size.
            view.setAlpha(MIN_ALPHA + (scaleFactor - MIN_SCALE)
                    / (1 - MIN_SCALE) * (1 - MIN_ALPHA));

        } else { // (1,+Infinity]
            // This page is way off-screen to the right.
            view.setAlpha(0);
        }
    }


}

循环滑动处理则在adapter里实现

public class ImagePagerAdapter extends PagerAdapter implements ViewPager.OnPageChangeListener {
    private static final String TAG = "state-viewpage";
    private Context context;
    private ViewPager viewPager;
    ArrayList<ImageView> views;
    private boolean mIsChanged = false;

    private LinearLayout llDotContainer;
    private int mCurrentPagePosition = FIRST_ITEM_INDEX;
    private static int POINT_LENGTH = 0;
    private static int FIRST_ITEM_INDEX = 1;
    private static int IMAGE_POINT_LENGTH = 0;

    private List<MessageInfo> mHomeMsgs;
    private ImageView[] dotImages;

    public ImagePagerAdapter(Context context, ArrayList<ImageView> viewpages, ViewPager viewPager,
                             LinearLayout llDotContainer, List<MessageInfo> homeMessages) {
        this.context = context;
        this.viewPager = viewPager;
        this.llDotContainer = llDotContainer;
        mHomeMsgs = homeMessages;

        this.viewPager.addOnPageChangeListener(this);
        views = viewpages;

        initCycleViews();
        initImageData();

        if (views.size() > 1) {
            refresDotsIndex(POINT_LENGTH / 2);
        }
    }

//这个方法就是将首尾两张图片分别加在两端
    private void initCycleViews() {
        //add two view
        IMAGE_POINT_LENGTH = views.size();

        if (views.size() >= 2) {
            POINT_LENGTH = views.size();
            ImageView prevFirst = new ImageView(context);
            Drawable firstDrawable = views.get(0).getDrawable();
            Drawable lastDrawable = views.get(views.size() - 1).getDrawable();

            prevFirst.setImageDrawable(lastDrawable);
            views.add(0, prevFirst);
            ImageView prevFirst1 = new ImageView(context);
            //prevFirst.setImageResource(R.drawable.ic_launcher);
            prevFirst1.setImageDrawable(firstDrawable);
            views.add(views.size(), prevFirst1);
            //init small dots
            initDots();
        } else {
            POINT_LENGTH = 0;
            FIRST_ITEM_INDEX = 0;
        }
    }

    //这个是图片的下标指示点，表示当前查看的图片是第几张，创建一个Linearlayout,然后动态添加imgview进去，selected状态来显示当前节点是否展示
    private void initDots() {
        if (IMAGE_POINT_LENGTH >= 2) {
            dotImages = new ImageView[IMAGE_POINT_LENGTH];
            for (int i = 0; i < IMAGE_POINT_LENGTH; i++) {
                ImageView dot = new ImageView(context);
                dot.setBackgroundResource(R.drawable.sel_dot_focused);
                if (i == 0) dot.setSelected(true);
                llDotContainer.addView(dot);
                dotImages[i] = dot;
            }
        }
    }

//这个函数是给初始数据，打开就是一个demo了，从网络下直接加载图片显示，url在数组里给出
    private void initImageData() {
//        for (int i = 0; i < arrarys.length + 2; i++) {
//            ImageView imageView = views.get(i);
////            view 0 1 2 3 4 5
////            data   4 1 2 3 4 0
//            if (i == 0) {
//                Picasso.with(context).load(arrarys[arrarys.length - 1]).into(imageView);
//            } else if (i == arrarys.length + 1) {
//                Picasso.with(context).load(arrarys[0]).into(imageView);
//            } else {
//                Picasso.with(context).load(arrarys[i-1]).into(imageView);
//            }
//        }
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        ImageView imageView = (ImageView) views.get(position);
        imageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //todo   页面点击事件在这里实现
            }
        });
        container.addView(imageView);
        return imageView;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView((View) object);
    }

    @Override
    public int getCount() {
        return views.size();
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == object;
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
    }

    @Override
    public void onPageSelected(final int position) {
        mIsChanged = true;
        if (position > POINT_LENGTH) {
            mCurrentPagePosition = FIRST_ITEM_INDEX;
        } else if (position < FIRST_ITEM_INDEX) {
            mCurrentPagePosition = POINT_LENGTH;
        } else {
            mCurrentPagePosition = position;
        }
        Log.i(TAG, "当前的位置是 " + mCurrentPagePosition);
    }

    @Override
    public void onPageScrollStateChanged(int state) {
        System.err.println("-------state------>" + state);
        System.err.println("-------state-vitem----->" + viewPager.getCurrentItem());
        switch (state) {
            //在滚动完成之后
            case ViewPager.SCROLL_STATE_IDLE:
                if (mIsChanged) {
                    mIsChanged = false;
                    viewPager.setCurrentItem(mCurrentPagePosition, false);
                    refresDotsIndex(mCurrentPagePosition - 1);
                    Log.i(TAG, "set current " + mCurrentPagePosition);
                }
                break;
        }
    }

    public void refresDotsIndex(int curr) {
        for (int i = 0; i < IMAGE_POINT_LENGTH; i++) {
            if (i == curr) {
                dotImages[i].setSelected(true);
            } else {
                dotImages[i].setSelected(false);
            }
        }
    }
}

最后再看布局文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/rel_msg_popup_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/mask_bg">

    <RelativeLayout
        android:id="@+id/rel_vp_container"
        android:layout_width="250dp"
        android:layout_height="300dp"
        android:background="@android:color/transparent"
        android:layout_centerInParent="true">

        <android.support.v4.view.ViewPager
            android:id="@+id/vp_msg_img"
            android:layout_width="500dp"
            android:layout_height="600dp"
            android:layout_centerInParent="true"
            android:flipInterval="30"
            android:persistentDrawingCache="animation" />

        <LinearLayout
            android:id="@+id/ll_dot_container"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignBottom="@id/vp_msg_img"
            android:layout_centerInParent="true"
            android:background="@android:color/transparent"
            android:orientation="horizontal" />
    </RelativeLayout>

    <ImageView
        android:id="@+id/iv_close"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/rel_vp_container"
        android:layout_centerInParent="true"
        android:layout_marginTop="10dp"
        android:src="@drawable/close" />
</RelativeLayout>

图标指示的小圆点selector文件

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@drawable/oval" android:state_selected="true"/>
    <item android:drawable="@drawable/oval_unsel" android:state_selected="false"/>

</selector>

静态效果图如下，在这也就不上实际效果图了，这个界面还是透明的界面，整个图片是悬浮在上面的效果，透明界面见 http://www.cnblogs.com/lovemo1314/p/6108777.html,