handler实现页面切换，小红点跟随移动

来源：互联网发布：mac图片文件夹在哪里编辑：程序博客网时间：2024/06/04 19:27

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

    <com.example.lenovo.lianxi.view.AutoShowView
        android:id="@+id/asv"
        android:layout_width="match_parent"
        android:layout_height="200dp">

</com.example.lenovo.lianxi.view.AutoShowView>

</RelativeLayout>

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

<android.support.v4.view.ViewPager
        android:id="@+id/vp_lunbo"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </android.support.v4.view.ViewPager>

</RelativeLayout>

public class MainActivity extends AppCompatActivity {
    protected static final String tag = "MainActivity";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

}
}

public class PicturePagerAdapter extends PagerAdapter {
private static final String tag = "PicturePagerAdapter";
List<ImageView> list;

    public PicturePagerAdapter(List<ImageView> imageViews) {
        this.list = imageViews;
    }

    @Override
    public int getCount() {
        // 确定要显示的数据量
        return Integer.MAX_VALUE;// 无限轮播
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        // 判断当前要显示的view是否等于标记object,true则显示
        return view == object;
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        position = position % list.size();
        Log.d(tag, "instantiateItem==" + position);
        // 无限轮播-因为position的值从0~Integer.MAX_VALUE
        View view = list.get(position);
        // 添加view到VIewPager中
        container.addView(view);
        return view;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        // 从容器中移除view
        Log.d(tag, "destroyItem==" + position);
        container.removeView((View) object);
    }
}

public class AutoShowView extends FrameLayout {
    private View view;
    private ViewPager vp_lunbo;
    private TextView tv_desc;
    private LinearLayout ll_points;
    private List<ImageView> datas;
    private PicturePagerAdapter adapter;
    private Handler handler;

final AutoScrollTask autoScrollTask = new AutoScrollTask();
protected int selectIndex;

public AutoShowView(Context context) {

this(context, null);
}

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

    public AutoShowView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initView(context);
        initData();
        initListener();
    }

    private void initView(Context context) {
        view = LayoutInflater.from(context).inflate(R.layout.view_autoshow,
                this);

        vp_lunbo = (ViewPager) view.findViewById(R.id.vp_lunbo);
        tv_desc = (TextView) view.findViewById(R.id.tv_desc);
        ll_points = (LinearLayout) view.findViewById(R.id.ll_points);

        datas = new ArrayList<ImageView>();
        adapter = new PicturePagerAdapter(datas);
        if (handler == null) {
            handler = new Handler();
        }
    }

    private void initData() {
        // 初始化图片数据
        initImageView();
        // 初始化点数据
        initPoints();

        vp_lunbo.setAdapter(adapter);
        // 设置ViewPager当前选中的位置,会调用instantiateItem，最终会选中item0
        // 原理：一个数减去其余数后肯定能被除数整除
        vp_lunbo.setCurrentItem(10000 - 10000 % datas.size());

autoScrollTask.start();
}

    private void initImageView() {
        for (int i = R.drawable.icon1; i < R.drawable.icon1 + 4; i++) {
            // 创建ImageView容器
            ImageView imageView = new ImageView(getContext());

            // 设置图片
            imageView.setImageResource(i);
            imageView.setScaleType(ImageView.ScaleType.FIT_XY);// 图片填充容器
            datas.add(imageView);// 添加到集合中
        }
    }

    private void initPoints() {
        // 因为每次页面改变都会调用该方法，所以进入该方法时先清空集合。
        ll_points.removeAllViews();

        for (int i = 0; i < datas.size(); i++) {
            View view = new View(getContext());
            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
                    10, 10);
            if (i == selectIndex) {
                tv_desc.setText("图片" + i + "的描述");
                view.setBackgroundResource(R.drawable.point_red);
            } else {
                view.setBackgroundResource(R.drawable.point_white);
            }
            params.leftMargin = 10;
            view.setLayoutParams(params);// 设置布局参数
            ll_points.addView(view);// 添加到点的容器中
        }
    }

    private void initListener() {
        // viewpager注册页面改变监听器
        vp_lunbo.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageSelected(int position) {
                // 页面选中调用
                selectIndex = position % datas.size();
                initPoints();// 红点跟着页面改变而移动
            }

            @Override
            public void onPageScrolled(int position, float positionOffset,
                                       int positionOffsetPixels) { // 页面滑动就调用
            }

            @Override
            public void onPageScrollStateChanged(int state) {
                // 页面状态改变调用

}
});

// viewpager 注册触摸事件监听器，实现自动轮播
vp_lunbo.setOnTouchListener(new OnTouchListener() {

            @Override
            public boolean onTouch(View v, MotionEvent event) {
                switch (event.getAction()) {
                    case MotionEvent.ACTION_DOWN:// 按下停止轮播
                        autoScrollTask.stop();
                        break;
                    case MotionEvent.ACTION_MOVE:

                        break;
                    case MotionEvent.ACTION_UP:// 松开，取消开始轮播
                    case MotionEvent.ACTION_CANCEL:
                        autoScrollTask.start();
                        break;

                    default:
                        break;
                }
                return false;// 不会影响其他view的事件分发
            }
        });
    }

/** 实现轮播图自动轮播 */

class AutoScrollTask implements Runnable {

        @Override
        public void run() {
            int currentItem = vp_lunbo.getCurrentItem();
            currentItem++;
            vp_lunbo.setCurrentItem(currentItem);
            start();
        }

        /**
         * 开始轮播
         */
        public void start() {
            handler.postDelayed(this, 2000);
        }

        /**
         * 停止轮播
         */
        public void stop() {
            handler.removeCallbacks(this);
        }
    }

}

阅读全文

0 1