Android BannerView通用封装详解

之前封装过一个，但总觉得不够优雅，就有了这个通用封装，很简洁，不知道够不够优雅，不过原来那个有跟随指示器和丝滑滑动效果，感兴趣可以看一下。

封装过程

1、自定义属性

selectPoint：选中指示器图标
normalPoint：未选中指示器图标
pointWidth：图标宽度
switchTime：轮播间隔事件
location：指示器位置，下中或下右

<declare-styleable name="NewBannerView">
   <attr name="selectPoint" format="reference" />
   <attr name="normalPoint" format="reference" />
   <attr name="pointWidth" format="dimension" />
   <attr name="switchTime" format="integer" />
   <attr name="location">
     <enum name="CENTER" value="0" />
     <enum name="RIGHT" value="1" />
   </attr>
 </declare-styleable>

2、初始化View
初始化ViewPager和指示器组合View

3、绑定数据源
通过setImageData设置轮播图数据源

4、绑定点击事件
通过OnPageClickListener绑定点击事件

5、开启关闭轮播
start和stop方法开启和关闭轮播

用法

xml中

<com.goldou.lovesee.view.NewBannerView
   android:id="@+id/bannerView"
   android:layout_width="match_parent"
   app:selectPoint="@drawable/red_point"
   app:normalPoint="@drawable/gray_point"
   app:switchTime="4000"
   app:location="RIGHT"
   android:layout_height="200dp" />

activity中

int[] imageList = {R.drawable.me_top, R.drawable.me_top, R.drawable.me_top, R.drawable.me_top};
   NewBannerView bannerView = view.findViewById(R.id.bannerView);
   bannerView.setImageData(imageList);
   bannerView.start();
   bannerView.setOnPageClickListener(new NewBannerView.OnPageClickListener() {
     @Override
     public void onPageClick(int position) {
       Toast.makeText(getActivity(), position + "", Toast.LENGTH_SHORT).show();
     }
   });

BannerView

public class NewBannerView extends RelativeLayout implements View.OnClickListener {
 private Context context;
 private int selectPoint, normalPoint;
 private float pointWidth = 7;
 private int location;
 private int CENTER = 0, RIGHT = 1;
 private int lastPosition = 0;
 private ViewPager viewPager;
 private int switchTime = 5000;
 private int[] images;
 private OnPageClickListener onPageClickListener;

private Handler handler = new Handler(new Handler.Callback() {
   @Override
   public boolean handleMessage(Message msg) {
     if (msg.what == 101) {
       viewPager.setCurrentItem(viewPager.getCurrentItem() + 1);
       start();
     }
     return false;
   }
 });

public NewBannerView(Context context) {
   this(context, null);
 }

public NewBannerView(Context context, AttributeSet attrs) {
   this(context, attrs, 0);
 }

public NewBannerView(Context context, AttributeSet attrs, int defStyleAttr) {
   super(context, attrs, defStyleAttr);
   this.context = context;
   initAttr(attrs);
 }

private void initAttr(AttributeSet attrs) {
   TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.NewBannerView);
   selectPoint = array.getResourceId(R.styleable.NewBannerView_selectPoint, R.mipmap.ic_launcher_round);
   normalPoint = array.getResourceId(R.styleable.NewBannerView_normalPoint, R.mipmap.ic_launcher_round);
   pointWidth = array.getDimension(R.styleable.NewBannerView_pointWidth, pointWidth);
   location = array.getInteger(R.styleable.NewBannerView_location, RIGHT);
   switchTime = array.getInteger(R.styleable.NewBannerView_switchTime, switchTime);
   array.recycle();
 }

public void setImageData(final int[] images) {
   this.images = images;
   final LinearLayout ll_point = new LinearLayout(context);
   LayoutParams layoutParams = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
   layoutParams.addRule(ALIGN_PARENT_BOTTOM, RelativeLayout.TRUE);
   layoutParams.bottomMargin = 20;
   if (location == CENTER) {
     layoutParams.addRule(CENTER_HORIZONTAL, RelativeLayout.TRUE);
   } else {
     layoutParams.addRule(ALIGN_PARENT_RIGHT, RelativeLayout.TRUE);
     layoutParams.rightMargin = 20;
   }
   LinearLayout.LayoutParams params1 = new LinearLayout.LayoutParams(UIUtil.dip2px(pointWidth), UIUtil.dip2px(pointWidth));
   LinearLayout.LayoutParams params2 = new LinearLayout.LayoutParams(UIUtil.dip2px(pointWidth), UIUtil.dip2px(pointWidth));
   params1.leftMargin = 0;
   params2.leftMargin = UIUtil.dip2px(pointWidth);
   for (int i = 0; i < images.length; i++) {
     ImageView point = new ImageView(context);
     if (i == 0) {
       point.setBackgroundResource(selectPoint);
       point.setLayoutParams(params1);
     } else {
       point.setBackgroundResource(normalPoint);
       point.setLayoutParams(params2);
     }
     ll_point.addView(point);
   }

viewPager = new ViewPager(context);
   viewPager.setAdapter(new BannerAdapter());
   viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
     @Override
     public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

}

@Override
     public void onPageSelected(int position) {
       position = position ％ images.length;
       if (lastPosition == position) {
         return;
       }
       ll_point.getChildAt(position).setBackgroundResource(selectPoint);
       ll_point.getChildAt(lastPosition).setBackgroundResource(normalPoint);
       lastPosition = position;
     }

@Override
     public void onPageScrollStateChanged(int state) {

}
   });
   LayoutParams layoutParams1 = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
   addView(viewPager, layoutParams1);
   addView(ll_point, layoutParams);
 }

public void start() {
   handler.sendEmptyMessageDelayed(101, switchTime);
 }

public void stop() {
   handler.removeCallbacksAndMessages(null);
 }

private int getCurrentItem() {
   return viewPager.getCurrentItem() ％ images.length;
 }

@Override
 public void onClick(View view) {
   onPageClickListener.onPageClick(getCurrentItem());
 }

public interface OnPageClickListener {
   void onPageClick(int position);
 }

public void setOnPageClickListener(OnPageClickListener onPageClickListener) {
   this.onPageClickListener = onPageClickListener;
 }

private class BannerAdapter extends PagerAdapter {

@Override
   public int getCount() {
     return Integer.MAX_VALUE;
   }

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

@Override
   public Object instantiateItem(ViewGroup container, int position) {
     position = position ％ images.length;
     ImageView imageView = new ImageView(context);
     imageView.setImageResource(images[position]);
     imageView.setScaleType(ImageView.ScaleType.FIT_XY);
     imageView.setOnClickListener(NewBannerView.this);
     container.addView(imageView);
     return imageView;
   }

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

来源：https://www.jianshu.com/p/594c95c98f62