自定义Banner轮播图

//依赖
compile 'com.github.bumptech.glide:glide:3.6.1'

//网络权限

    
    

//在res/values目录下新建attrs.xml


    
        
        
    

//在res/drawable新建dot_normal.xml


    
    

//在res/drawable新建dot_selected.xml


    
    

//组合控件--轮播图
public class Banner extends FrameLayout implements ViewPager.OnPageChangeListener {
    private final int DELAY_TIME = 5000;//自动轮播时间
    private List mUrls;
    private List mViewpagerViews;
    private List mDotImageviews;
    private Context context;
    private int size;//圆点的大小
    private int margin;//圆点的间距
    private int count;//viewpager中view的数量
    private ViewPager mViewPager;
    private LinearLayout mDotlayout;//圆点布局
    private MyPager mPagerAdapter;

    private int currentItem;//当前viewpager索引
    private Handler handler = new Handler();
    private BannerClicklistener mBannerClicklistener;
    public Banner(@NonNull Context context) {
        super(context);

        init(context, null);
    }

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

    public Banner(@NonNull Context context, @Nullable AttributeSet attrs, @AttrRes int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(context, attrs);
    }
    /**
     * 初始化数据
     *
     * @param context
     * @param attrs
     */
    private void init(Context context, AttributeSet attrs) {
        this.context = context;
        mUrls = new ArrayList<>();
        mViewpagerViews = new ArrayList<>();
        mDotImageviews = new ArrayList<>();
        //拿到自定义的属性数组
        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.Banner);
        //得到数组里的自定义的size（圆点大小）
        size = typedArray.getDimensionPixelSize(R.styleable.Banner_size, 10);
        //得到数组里的自定义的margin（圆点间距）
        margin = typedArray.getDimensionPixelSize(R.styleable.Banner_margin, 10);
        typedArray.recycle();//通知jvm的垃圾回收器，当你回收对象的时候，一定要把我回收了
        View view = LayoutInflater.from(context).inflate(R.layout.banner_layout, this, true);
        mViewPager = view.findViewById(R.id.viewpager);
        mDotlayout = view.findViewById(R.id.layout_dot);
        //添加viewpager页面改变监听
        mViewPager.addOnPageChangeListener(this);
    }
    /**
     * 绘制自定义view的所有元素
     */
    public void display() {
        //绘制viewpager
        drawViewpager();
        //绘制圆点
        drawDots();
        //设置自动滚动
        setAuto();
    }
    /**
     * 设置自动滚动
     */
    private void setAuto() {
        handler.postDelayed(mTask, DELAY_TIME);
    }
    /**
     * 定时任务
     */
    Runnable mTask = new Runnable() {
        @Override
        public void run() {
            currentItem++;
            if (currentItem >= count) {
                currentItem = 0;
            }
            mViewPager.setCurrentItem(currentItem);
            handler.postDelayed(this, DELAY_TIME);
        }
    };
    /**
     * 传urls
     *
     * @param urls
     */
    public Banner loadData(List urls) {
        this.mUrls = urls;
        this.count = urls.size();
        return this;
    }
    /**
     * 绘制圆点
     */
    private void drawDots() {

        for (int i = 0; i < count; i++) {
            ImageView iv = new ImageView(context);
            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(size, size);
            params.leftMargin = margin;
            params.rightMargin = margin;
            iv.setLayoutParams(params);
            mDotImageviews.add(iv);
            if (i == 0) {
                iv.setImageResource(R.drawable.dot_selected);
            } else {
                iv.setImageResource(R.drawable.dot_normal);
            }
            mDotlayout.addView(iv);
        }
    }
    private void drawViewpager() {
        for (int i = 0; i < count; i++) {
            ImageView iv = new ImageView(context);
            iv.setScaleType(ImageView.ScaleType.CENTER_CROP);
            mViewpagerViews.add(iv);
        }
        if (mViewpagerViews != null) {
            mPagerAdapter = new MyPager();
            mViewPager.setAdapter(mPagerAdapter);
        }
    }

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

    }
    /**
     * 切换页面的监听
     * @param position
     */
    @Override
    public void onPageSelected(int position) {

        for (int i = 0; i < count; i++) {
            if (i == position) {
                mDotImageviews.get(i).setImageResource(R.drawable.dot_selected);
            } else {
                mDotImageviews.get(i).setImageResource(R.drawable.dot_normal);
            }
        }
    }

    @Override
    public void onPageScrollStateChanged(int state) {

    }
    class MyPager extends PagerAdapter {

        @Override
        public int getCount() {
            return mViewpagerViews.size();
        }
        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == object;
        }
        @Override
        public Object instantiateItem(ViewGroup container, final int position) {

            ImageView view = mViewpagerViews.get(position);
            container.addView(view);
            view.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View view) {
                    //实现点击逻辑
                    mBannerClicklistener.onClickListener(position);
                }
            });
            System.out.println("urls:"+mUrls.get(position));
            Glide.with(context).load(mUrls.get(position)).into(view);
            return view;
        }

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

    /**
     * 处理自动轮播和手动滑动的冲突
     *
     * @param ev
     * @return
     */
    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        int action = ev.getAction();
        if (action == MotionEvent.ACTION_DOWN || action == MotionEvent.ACTION_MOVE) {
            stopAuto();
        } else if (action == MotionEvent.ACTION_UP) {
            setAuto();
        }
        return super.dispatchTouchEvent(ev);
    }
    /**
     * 取消自动轮播任务
     */
    private void stopAuto() {
        handler.removeCallbacks(mTask);//取消任务
    }

    /**
     * 供外部调用者调用的接口类
     */
    public interface BannerClicklistener {
        void onClickListener(int pos);
    }
    /**
     * 供外部调用者初始化接口对象
     */
    public void setBannerClicklistener(BannerClicklistener bannerClicklistener) {
        this.mBannerClicklistener = bannerClicklistener;
    }
    //取消轮播任务
    public void cancel(){
        handler.removeCallbacks(mTask);
    }
}

//组合控件--XML


    

    

//main
public class MainActivity extends AppCompatActivity {
    private Banner banner;
    private List urls;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        getSupportActionBar().hide();
        banner = (Banner) findViewById(R.id.banner);

        urls = new ArrayList<>();
        urls.add("https://www.zhaoapi.cn/images/quarter/ad1.png");
        urls.add("https://www.zhaoapi.cn/images/quarter/ad2.png");
        urls.add("https://www.zhaoapi.cn/images/quarter/ad3.png");
        urls.add("https://www.zhaoapi.cn/images/quarter/ad4.png");


        //解耦
        banner.loadData(urls).display();//构建者模式返回对象本身
//        banner.display();

        banner.setBannerClicklistener(new Banner.BannerClicklistener() {
            @Override
            public void onClickListener(int pos) {

                Toast.makeText(MainActivity.this, "pos====" + pos, Toast.LENGTH_SHORT).show();
            }
        });
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (banner != null) {
            banner.cancel();
            banner = null;
        }
    }
}

//main的XML