Android自定义图片轮播Banner控件使用解析

 <com.xiaomai.bannerview.BannerView
    android:id="@+id/bannerView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:aspectRatio="1.5"
    app:defaultSrc="@mipmap/ic_launcher"
    app:indicatorBackground="@color/white"
    app:indicatorHeight="50dp"
    app:indicatorPositionSize="8dp"
    app:updateTime="3000" />

<resources>

  <declare-styleable name="BannerView">
    <attr name="aspectRatio" format="float" />  <!-- 宽高比 -->
    <attr name="defaultSrc" format="integer|reference" />   <!-- 占位图 -->
    <attr name="updateTime" format="integer" />   <!-- 图片切换时间 -->
    <attr name="indicatorVisible" format="boolean" /> <!-- 是否显示指示器 -->
    <attr name="indicatorHeight" format="dimension" /> <!-- 指示器的高度 -->
    <attr name="indicatorBackground" format="color|reference" />  <!-- 指示器的背景颜色 -->
    <attr name="indicatorPositionSize" format="dimension" /> <!-- 指示点的大小 -->
  </declare-styleable>

</resources>

public class BannerView extends RelativeLayout {

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

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

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

private Context context;

  private Handler handler;
  private ImageLoader imageLoader;
  private DisplayImageOptions options;
  private boolean isHaveHandler = true;// 当用户点击轮播图时，取消handler队列，也就是取消滚动
  // 控件Start
  private ViewPager viewPager;
  private LinearLayout indicator;// 指示器
  private onItemClickListener listener;
  // 控件End

  // 自定义属性Start
  private float mAspectRatio; // 宽高比
  private int defaultImageResource; // 默认占位图
  private int updateTime; // 图片切换的时间间隔,默认3秒
  private boolean showIndicator; // 是否显示指示器,默认显示
  private int indicatorHeight;// 指示器的高度,默认35dp
  private int indicatorPositionSize; // 指示器的大小
  private int indicatorBackground; // 指示器的背景颜色
  // 自定义属性End
  // 数据Start
  private int imageCount;
  private int lastPosition;

  private List<Integer> imageResources;
  private List<Image> imageUrls;
  // 数据End

public BannerView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    parseCustomAttributes(context, attrs);
    this.context = context;
    handler = new Handler();
    imageLoader = ImageLoader.getInstance();
    options = HSApplication.getDisplayOptions().build();
    initViews();
  }
  /**
   * 解析自定义属性
   *
   * @param context
   * @param attrs
   */
  private void parseCustomAttributes(Context context, AttributeSet attrs) {
    TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.BannerView);
    mAspectRatio = typedArray.getFloat(R.styleable.BannerView_aspectRatio, 0f);
    defaultImageResource = typedArray.getResourceId(R.styleable.BannerView_defaultSrc,
        R.drawable.about_us);
    updateTime = typedArray.getInt(R.styleable.BannerView_updateTime, 3000);
    showIndicator = typedArray.getBoolean(R.styleable.BannerView_indicatorVisible, true);
    indicatorHeight = (int) (typedArray.getDimension(R.styleable.BannerView_indicatorHeight,
        Utils.dip2px(context, 35)));
    indicatorBackground = typedArray.getResourceId(R.styleable.BannerView_indicatorBackground,
        R.color.white_alpha00);
    indicatorPositionSize = (int) typedArray.getDimension(
        R.styleable.BannerView_indicatorPositionSize, Utils.dip2px(context, 5));
    typedArray.recycle();
  }
  private void initViews() {
    viewPager = new ViewPager(context);
    viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
      @Override
      public void onPageScrolled(int position, float positionOffset,
          int positionOffsetPixels) {

      }

      @Override
      public void onPageSelected(int position) {
        if (showIndicator) {
          for (int i = 0; i < indicator.getChildCount(); i++) {
            indicator.getChildAt(i).setSelected(false);
          }
          indicator.getChildAt(position % imageCount).setSelected(true);
        }
        lastPosition = position;
      }

      @Override
      public void onPageScrollStateChanged(int state) {
        switch (state) {
          case ViewPager.SCROLL_STATE_IDLE:// 空闲状态
            if (!isHaveHandler) {
              isHaveHandler = true;
              handler.postDelayed(updateRunnable, updateTime);
            }
            break;
          case ViewPager.SCROLL_STATE_DRAGGING:// 用户滑动状态
            handler.removeCallbacks(updateRunnable);
            isHaveHandler = false;
            break;
        }
      }
    });
    addView(viewPager, new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
        ViewGroup.LayoutParams.WRAP_CONTENT));

    if (showIndicator) {
      indicator = new LinearLayout(context);
      indicator.setOrientation(LinearLayout.HORIZONTAL);
      indicator.setGravity(Gravity.CENTER);
      indicator.setBackgroundResource(indicatorBackground);
      RelativeLayout.LayoutParams layoutParams = new LayoutParams(
          ViewGroup.LayoutParams.MATCH_PARENT, indicatorHeight);
      layoutParams.addRule(ALIGN_PARENT_BOTTOM);
      addView(indicator, layoutParams);
    }
}

 public void setImageResources(List<Integer> imageResources) {
    if (imageResources == null || imageResources.size() == 0) {
      throw new RuntimeException("图片资源为空");
    }
    this.imageResources = imageResources;
    imageCount = imageResources.size();
  }

  public void setImageUrls(List<Image> imageUrls) {
    if (imageUrls == null || imageUrls.size() == 0) {
      throw new RuntimeException("图片地址资源为空");
    }
    this.imageUrls = imageUrls;
    imageCount = imageUrls.size();
    loadImages();
  }

  private void loadImages() {
    if (showIndicator) {
      addIndicationPoint();
    }
    viewPager.setAdapter(new MyViewPageAdapter());
    viewPager.setCurrentItem(200 - (200 % imageCount));
    handler.removeCallbacks(updateRunnable);
    handler.postDelayed(updateRunnable, updateTime);
  }

  /**
   * 添加指示点到指示器中
   */
  private void addIndicationPoint() {
    // 防止刷新重复添加
    if (indicator.getChildCount() > 0) {
      indicator.removeAllViews();
    }
    View pointView;
    int margin = Utils.dip2px(context, 5f);
    LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
        indicatorPositionSize, indicatorPositionSize);
    layoutParams.setMargins(margin, margin, margin, margin);

    for (int i = 0; i < imageCount; i++) {
      pointView = new View(context);
      pointView.setBackgroundResource(R.drawable.indicator_selector);
      if (i == lastPosition) {
        pointView.setSelected(true);
      } else {
        pointView.setSelected(false);
      }
      indicator.addView(pointView, layoutParams);
    }
  }

  private class MyViewPageAdapter 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, final int position) {
      final ImageView imageView = new ImageView(container.getContext());
      imageView.setImageResource(defaultImageResource);
      imageView.setScaleType(ImageView.ScaleType.FIT_XY);
      final Image image = imageUrls.get(position % imageCount);
      imageLoader.displayImage(image.getImageUrl(), imageView, options);
      imageView.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
          if (listener != null) {
            listener.onClick(v, position % imageCount, image.getAction(),
                image.getUrl());
          }
        }
      });
      container.addView(imageView);
      return imageView;
    }

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

  private Runnable updateRunnable = new Runnable() {
    @Override
    public void run() {
      viewPager.setCurrentItem(lastPosition + 1);
      handler.postDelayed(updateRunnable, updateTime);
    }

/**
   * 点击监听回调事件
   */
  public interface onItemClickListener {
    void onClick(View view, int position, String action, String url);
  }

  public void setOnItemClickListener(onItemClickListener listener) {
    this.listener = listener;
  }