Android Banner 简单实现

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/qq_24078843/article/details/78864756

参考 http://www.jianshu.com/p/f8bf9e8b0a39

ViewPageAdapter

public class ViewPagerAdapter extends PagerAdapter {

    private List<Integer> data;

    public ViewPagerAdapter(List<Integer> data) {
        this.data = data;
    }

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

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

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        ImageView imageView = new ImageView(container.getContext());
        imageView.setScaleType(ImageView.ScaleType.CENTER);
        imageView.setBackgroundResource(data.get(position));
        container.addView(imageView);
        return imageView;
//        return super.instantiateItem(container, position);
    }

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

布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.alex.viewpagerdemo.MainActivity">

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <android.support.v4.view.ViewPager
            android:id="@+id/viewpager"
            android:layout_width="match_parent"
            android:layout_height="200dp"></android.support.v4.view.ViewPager>

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="40dp"
            android:layout_gravity="bottom"
            android:background="#9977">

            <TextView
                android:id="@+id/banner_title"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:text="怎么了"
                android:gravity="center_vertical"
                android:textColor="@android:color/white"
                android:paddingLeft="20dp"/>

            <TextView
                android:id="@+id/banner_indicator"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:text="1/4"
                android:gravity="center_vertical"
                android:textColor="@android:color/white"
                android:layout_alignParentRight="true"
                android:layout_marginRight="20dp"/>

        </RelativeLayout>

    </FrameLayout>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="SortLayout"
        android:textAllCaps="false"
        android:onClick="sort"/>

</LinearLayout>

MainActivity

public class MainActivity extends AppCompatActivity {

    ViewPager viewPager;
    ViewPagerAdapter adapter;
    List<Integer> data;
    List<String> titleData;
    int currentPage = 0;
    boolean viewPagerScrollStatus = false; //标志位,当在手动翻页时,自动翻页暂停

    TextView title, indicator;

    Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            if (!viewPagerScrollStatus) {
                viewPager.setCurrentItem(++currentPage);
            }
            handler.sendEmptyMessageDelayed(1, 1000);
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        viewPager = (ViewPager) findViewById(R.id.viewpager);
        title = (TextView) findViewById(R.id.banner_title);
        indicator = (TextView) findViewById(R.id.banner_indicator);
        data = new ArrayList<>(); titleData = new ArrayList<>();
        data.add(R.mipmap.t);     titleData.add("4.哦");
        data.add(R.mipmap.a);     titleData.add("1.怎么了");
        data.add(R.mipmap.b);     titleData.add("2.没事");
        data.add(R.mipmap.c);     titleData.add("3.那好吧");
        data.add(R.mipmap.t);     titleData.add("4.哦");
        data.add(R.mipmap.a);     titleData.add("1.怎么了");
        adapter = new ViewPagerAdapter(data);
        viewPager.setAdapter(adapter);

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

            }

            @Override
            public void onPageSelected(int position) {
                //头尾衔接,无限循环
                if (position == data.size() - 1) {
                    currentPage = 1;
                } else if (position == 0) {
                    currentPage = data.size() - 2;
                } else {
                    currentPage = position;
                }
            }

            @Override
            public void onPageScrollStateChanged(int state) {
                if (state == ViewPager.SCROLL_STATE_IDLE) {
                    viewPagerScrollStatus = false;
                    viewPager.setCurrentItem(currentPage, false);
                    title.setText(titleData.get(currentPage));
                    indicator.setText(currentPage + "/" + (titleData.size() - 2));
                } else {
                    viewPagerScrollStatus = true;
                }
            }
        });
        handler.sendEmptyMessageDelayed(1, 1000);

        viewPager.setPageTransformer(true, new ViewPager.PageTransformer() {
            @Override
            public void transformPage(View page, float position) {

                int width = page.getWidth();
                //我们给不同状态的页面设置不同的效果
                //通过position的值来分辨页面所处于的状态
                if (position < -1) {//滑出的页面
                    page.setScrollX((int) (width * 0.75 * -1));
                } else if (position <= 1) {//[-1,1]
                    if (position < 0) {//[-1,0]
                        page.setScrollX((int) (width * 0.75 * position));
                    } else {//[0,1]
                        page.setScrollX((int) (width * 0.75 * position));
                    }
                } else {//即将滑入的页面
                    page.setScrollX((int) (width * 0.75));
                }
            }
        });
    }

    public void sort(View v) {
        startActivity(new Intent(this, SortLayoutActivity.class));
    }
}

效果