項目開發(fā)中遇到要在廣告屏上顯示廣告視頻切換的功能蚓峦，由于是系統(tǒng)應(yīng)用開發(fā)這和常規(guī)App開發(fā)不一樣卵迂，涉及到焦點(diǎn)搶占，需要自定義輪播和視頻播放器请垛。因此需要自己自定義的邏輯催训，為了方便使用我們先自定義一個view.

public class Banner extends RelativeLayout
{
    private ViewPager viewPager;
    private final int UPTATE_VIEWPAGER = 100;
    //圖片默認(rèn)時間間隔
    private int imgDelyed = 2000;
    //每個位置默認(rèn)時間間隔，因為有視頻的原因
    private int delyedTime = 2000;
    //默認(rèn)顯示位置宗收，為實現(xiàn)無限輪播
    private int autoCurrIndex = 1;
    //是否自動播放
    private boolean isAutoPlay = false;

    public Banner(Context context)
    {
        super(context);
        init();
    }

    public Banner(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        init();
    }

    public Banner(Context context, AttributeSet attrs, int defStyleAttr)
    {
        super(context, attrs, defStyleAttr);
        init();
    }

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    public Banner(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)
    {
        super(context, attrs, defStyleAttr, defStyleRes);
        init();
    }

    private void init()
    {
        viewPager = new ViewPager(getContext());
        LinearLayout.LayoutParams vp_param = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);
        viewPager.setLayoutParams(vp_param);
        this.addView(viewPager);
    }
}

很簡單漫拭，就實現(xiàn)了一些初始化，然后在布局里是這樣的

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.test.net.Banner
        android:id="@+id/banner"
        android:layout_width="match_parent"
        android:layout_height="200dp"></com.test.net.Banner>

</RelativeLayout>

引用我們自定義的view混稽，viewpage有了采驻，我們可以準(zhǔn)備PagerAdapter

public class BannerViewAdapter extends PagerAdapter
{
    private List<View> listBean;

    public BannerViewAdapter(List<View> list){
        if (list == null){
            list = new ArrayList<>();
        }
        this.listBean = list;
    }

    public void setDataList(List<View> list){
        if (list != null && list.size() > 0){
            this.listBean = list;
        }
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position)
    {
        View view = listBean.get(position);
        container.addView(view);
        return view;
    }

    @Override
    public int getItemPosition(Object object)
    {
        return POSITION_NONE;
    }

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

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

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

}

沒什么特別的，getItemPosition()是切換數(shù)據(jù)用的匈勋，后面有提到礼旅，好了我們來看看Activity

public class BannerActivity extends AppCompatActivity
{

    private Banner banner;
    private List<String> list;
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_banner);
        banner = (Banner) findViewById(R.id.banner);
        initData();
        initView();
    }

    private void initData(){
        HttpProxyCacheServer proxy = MApplication.getProxy(getApplicationContext());
        String proxyUrl = proxy.getProxyUrl("http://fs.mv.web.kugou.com/201805151034/301b4249052e4f77917f02c1903e3370/G131/M06/0D/00/ww0DAFr5qtqACRUoAh-sVLABkV8377.mp4");
        String proxyUrl2 = proxy.getProxyUrl("http://fs.mv.web.kugou.com/201805151530/498716f6f332829687bbf077e252a083/G133/M05/1F/19/xQ0DAFrwJs6AHgs6AbSCfVQb4IQ631.mp4");

        list = new ArrayList<>();
        list.add(proxyUrl);
        list.add("http://img2.imgtn.bdimg.com/it/u=3817131034,1038857558&fm=27&gp=0.jpg");
        list.add("http://img1.imgtn.bdimg.com/it/u=4194723123,4160931506&fm=200&gp=0.jpg");
        list.add(proxyUrl2);
        list.add("http://img5.imgtn.bdimg.com/it/u=1812408136,1922560783&fm=27&gp=0.jpg");
    }

    private void initView(){
        banner.setDataList(list);
        banner.setImgDelyed(5000);
        banner.autoBanner();
        banner.startAutoPlay();
    }
}

initData，初始化數(shù)據(jù)洽洁，HttpProxyCacheServer是用的一個視頻緩存庫[AndroidVideoCache]痘系，initView我們主要完成的東西，先看看setDataList()

public void setDataList(List<String> dataList){
        if (dataList == null){
            dataList = new ArrayList<>();
        }
        //用于顯示的數(shù)組
        if (views == null)
        {
            views = new ArrayList<>();
        }else {
            views.clear();
        }

        LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
        RequestOptions options = new RequestOptions();
        options.centerCrop();
        //數(shù)據(jù)大于一條饿自，才可以循環(huán)
        if (dataList.size() > 1)
        {
            autoCurrIndex = 1;
            //循環(huán)數(shù)組汰翠，將首位各加一條數(shù)據(jù)
            for (int i = 0; i < dataList.size() + 2; i++)
            {
                String url;
                if (i == 0)
                {
                    url = dataList.get(dataList.size() - 1);
                } else if (i == dataList.size() + 1)
                {
                    url = dataList.get(0);
                } else
                {
                    url = dataList.get(i - 1);
                }

                if (MimeTypeMap.getFileExtensionFromUrl(url).equals("mp4"))
                {
                    MVideoView videoView = new MVideoView(getContext());
                    videoView.setLayoutParams(lp);
                    videoView.setVideoURI(Uri.parse(url));
                    videoView.start();
                    views.add(videoView);
                } else
                {
                    ImageView imageView = new ImageView(getContext());
                    imageView.setLayoutParams(lp);
                    imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
                    Glide.with(getContext()).load(url).apply(options).into(imageView);
                    views.add(imageView);
                }
            }
        }else if(dataList.size() == 1){
            autoCurrIndex = 0;
            String url = dataList.get(0);
            if (MimeTypeMap.getFileExtensionFromUrl(url).equals("mp4"))
            {
                MVideoView videoView = new MVideoView(getContext());
                videoView.setLayoutParams(lp);
                videoView.setVideoURI(Uri.parse(url));
                videoView.start();
                //監(jiān)聽視頻播放完的代碼
                videoView.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {

                    @Override
                    public void onCompletion(MediaPlayer mPlayer) {
                        mPlayer.start();
                        mPlayer.setLooping(true);
                    }
                });
                views.add(videoView);
            } else
            {
                ImageView imageView = new ImageView(getContext());
                imageView.setLayoutParams(lp);
                imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
                Glide.with(getContext()).load(url).apply(options).into(imageView);
                views.add(imageView);
            }
        }
    }

解釋一下，先集合初始化璃俗，然后判斷集合長度奴璃，分大于1，和小于1
一城豁、大于1苟穆，可以無限循環(huán)
1、采用集合首尾各加一條數(shù)據(jù)來進(jìn)行循環(huán)，具體原因略
2雳旅、根據(jù)后綴來判斷是視頻還是圖片跟磨，目前視頻我只判斷MP4的，MimeTypeMap.getFileExtensionFromUrl()是Android自帶的
3攒盈、根據(jù)不同的類型創(chuàng)建不同的View抵拘，加入集合，MVideoView 是為了處理視頻不全屏做的處理型豁，圖片用的Glide
二僵蛛、等于1，不能無限循環(huán)
如果是視頻迎变，那么這個視頻要可以循環(huán)播放充尉，所以加入播放完成監(jiān)聽，圖片不變

public void setImgDelyed(int imgDelyed){
        this.imgDelyed = imgDelyed;
}

設(shè)置圖片播放間隔

public void startBanner()
    {
        mAdapter = new BannerViewAdapter(views);
        viewPager.setAdapter(mAdapter);
        viewPager.setOffscreenPageLimit(1);
        viewPager.setCurrentItem(autoCurrIndex);
        viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener()
        {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels)
            {

            }

            @Override
            public void onPageSelected(int position)
            {
                Log.d("TAG","position:"+position);
                //當(dāng)前位置
                autoCurrIndex = position;
                getDelayedTime(position);
            }

            @Override
            public void onPageScrollStateChanged(int state)
            {
                Log.d("TAG",""+state);

                //移除自動計時
                mHandler.removeCallbacks(runnable);

                //ViewPager跳轉(zhuǎn)
                int pageIndex = autoCurrIndex;
                if(autoCurrIndex == 0){
                    pageIndex = views.size()-2;
                }else if(autoCurrIndex == views.size() - 1){
                    pageIndex = 1;
                }
                if (pageIndex != autoCurrIndex) {
                    //無滑動動畫衣形，直接跳轉(zhuǎn)
                    viewPager.setCurrentItem(pageIndex, false);
                }

                //停止滑動時驼侠，重新自動倒計時
                if (state == 0 && isAutoPlay && views.size() > 1){
                    View view1 = views.get(pageIndex);
                    if (view1 instanceof VideoView){
                        final VideoView videoView = (VideoView) view1;
                        int current = videoView.getCurrentPosition();
                        int duration = videoView.getDuration();
                        delyedTime = duration - current;
                        //某些時候，某些視頻谆吴，獲取的時間無效倒源，就延時10秒，重新獲取
                        if (delyedTime <= 0){
                            time.getDelyedTime(videoView,runnable);
                            mHandler.postDelayed(time,imgDelyed);
                        }else {
                            mHandler.postDelayed(runnable,delyedTime);
                        }
                    }else {
                        delyedTime = imgDelyed;
                        mHandler.postDelayed(runnable,delyedTime);
                    }
                    Log.d("TAG",""+pageIndex+"--"+autoCurrIndex);
                }
            }
        });
    }

重中之重句狼，我們一點(diǎn)點(diǎn)來說笋熬，各種初始化我就不解釋了，viewPager.setCurrentItem(autoCurrIndex);鲜锚，初始化顯示的位置突诬，數(shù)據(jù)大于1時，初始化顯示1的位置芜繁，因為0的位置是假數(shù)據(jù)旺隙，數(shù)據(jù)等于1的時候，初始化顯示0的位置骏令，然后添加頁面切換監(jiān)聽蔬捷。
onPageSelected：記錄當(dāng)前位置，而且如果是視頻榔袋，就進(jìn)行播放周拐，具體代碼后面提到
onPageScrollStateChanged：移除自動輪播，且判斷當(dāng)前頁面是否是臨界凰兑，并進(jìn)行跳轉(zhuǎn)妥粟，然后根據(jù)條件判斷是否進(jìn)行自動輪播，這地方有一點(diǎn)就是在獲取視頻的總長和已播放長度時吏够，有時會失敗勾给，可能是因為為視頻還未真正加載滩报，所以我做了一個判斷，當(dāng)小于0的時候播急，用handler來做一個延時任務(wù)脓钾，延時時間是圖片輪播時間，延時結(jié)束后再次獲取視頻的總長和已播放長度桩警，唯一問題就是視頻可能很短可训，暫時沒想到其他解決方法。那么time捶枢，和runnable是這樣的

/**
     * 發(fā)消息握截，進(jìn)行循環(huán)
     */
    private Runnable runnable = new Runnable()
    {
        @Override
        public void run()
        {
            mHandler.sendEmptyMessage(UPTATE_VIEWPAGER);
        }
    };

    /**
     * 這個類，恩柱蟀，獲取視頻長度川蒙，以及已經(jīng)播放的時間
     */
    private class Time implements Runnable{

        private VideoView videoView;
        private Runnable runnable;

        public void getDelyedTime(VideoView videoView,Runnable runnable){
            this.videoView = videoView;
            this.runnable = runnable;
        }
        @Override
        public void run()
        {
            int current = videoView.getCurrentPosition();
            int duration = videoView.getDuration();
            int delyedTime = duration - current;
            mHandler.postDelayed(runnable,delyedTime);
        }
    }

Time本不想這樣寫蚜厉，需要初始化對象长已，而且得賦值，但是在幾個地方都有用到昼牛，初始化沒寫术瓮，相信都會，如果你不想這樣寫贰健，可以這樣

mHandler.postDelayed(new Runnable() {
                @Override
                public void run()
                {
                    int current = videoView.getCurrentPosition();
                    int duration = videoView.getDuration();
                    int delyedTime = duration - current;
                    mHandler.postDelayed(runnable,delyedTime);
                }
            },imgDelyed);

用new Runnable替換time就好了胞四，具體怎么弄，看喜好

 /**
     * 獲取delyedTime
     * @param position 當(dāng)前位置
     */
    private void getDelayedTime(int position){
        View view1 = views.get(position);
        if (view1 instanceof VideoView){
            VideoView videoView = (VideoView) view1;
            videoView.start();
            videoView.seekTo(0);
            delyedTime = videoView.getDuration();
            time.getDelyedTime(videoView,runnable);
        }else {
            delyedTime = imgDelyed;
        }
    }

獲取某個位置的輪播時間伶椿，又出現(xiàn)了time的身影辜伟，本不應(yīng)該出現(xiàn)的，這個方法是為其他地方服務(wù)的

//開啟自動循環(huán)
    public void startAutoPlay(){
        isAutoPlay = true;
        if (views.size() > 1){
            getDelayedTime(autoCurrIndex);
            if (delyedTime <= 0){
                mHandler.postDelayed(time,imgDelyed);
            }else {
                mHandler.postDelayed(runnable,delyedTime);
            }
        }
    }

理一下邏輯脊另，getDelayedTime()獲取delyedTime 导狡，小于0肯定是視頻，而且還沒獲取到偎痛，那么延時旱捧，其他就是要么圖片，要么視頻獲取到時間了踩麦，那么再加上一個handler就可以運(yùn)行了

//接受消息實現(xiàn)輪播
    private Handler mHandler = new Handler() {
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case UPTATE_VIEWPAGER:
                    viewPager.setCurrentItem(autoCurrIndex+1);
                    break;
            }
        }
    };

關(guān)于這個autoCurrIndex為什么沒有越界處理枚赡，而不擔(dān)心越界，這個主要在onPageScrollStateChanged里面
1谓谦、假如數(shù)組長度為3贫橙，經(jīng)過處理會變成5，記住0和4反粥，是偽數(shù)據(jù)卢肃，為了過度動畫的
2谓松、當(dāng)autoCurrIndex = position = 0的時候 會直接用viewPager.setCurrentItem(pageIndex, false);跳到3的位置，此時autoCurrIndex = position = 3
3践剂、當(dāng)autoCurrIndex = position = 4的時候 會直接用viewPager.setCurrentItem(pageIndex, false);跳到1的位置鬼譬，此時autoCurrIndex = position = 1
具體解釋一下流程就是：當(dāng)頁面開始動的時候onPageScrollStateChanged –>state = 1,然后onPageScrollStateChanged –>state = 2，然后執(zhí)行onPageSelected(),改變autoCurrIndex 逊脯，然后onPageScrollStateChanged –>state = 0优质。也就是說autoCurrIndex 在變成0或4的時候會立刻執(zhí)行onPageScrollStateChanged –>state = 0，判斷后執(zhí)行viewPager.setCurrentItem(pageIndex, false);跳到其他位置军洼，以上流程又重新走一遍巩螃，但autoCurrIndex 已經(jīng)不為0或4了。所以0或4的存在非常短匕争，也就不會產(chǎn)生影響避乏。

public void dataChange(List<String> list){
        if (list != null && list.size()>0)
        {
            //改變資源時要重新開啟循環(huán)，否則會把視頻的時長賦給圖片甘桑，或者相反
            //因為delyedTime也要改變拍皮，所以要重新獲取delyedTime
            mHandler.removeCallbacks(runnable);
            setDataList(list);
            mAdapter.setDataList(views);
            mAdapter.notifyDataSetChanged();
            viewPager.setCurrentItem(autoCurrIndex,false);
            //開啟循環(huán)
            if (isAutoPlay && views.size() > 1){
                getDelayedTime(autoCurrIndex);
                if (delyedTime <= 0){
                    mHandler.postDelayed(time,imgDelyed);
                }else {
                    mHandler.postDelayed(runnable,delyedTime);
                }
            }
        }
    }

切換數(shù)據(jù)捧搞，沒什么好說的誉己，關(guān)于viewpage,數(shù)據(jù)切換不立刻刷新妓柜，我就不說了肤寝，反正我是重寫了public int getItemPosition(Object object)慨亲，最后資源釋放体捏，反正就是能放什么就放什么就對了.總的來說腐泻，有兩點(diǎn)纵搁，1是獲取視頻時長的問題窄做，2是viewpage的緩存會導(dǎo)致視頻未顯示就開始播放了