ANDROID笔记:使用动画替代viewpager的header

package com.example.baofenanim;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.TranslateAnimation;
import android.widget.Button;
import android.widget.HorizontalScrollView;
import android.widget.ImageView;

public class MainActivity extends Activity {
    LayoutInflater inflater;
    // 测试的数据集
    List<View> list = new ArrayList<View>();
    // 滑块状态
    int state = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        inflater = LayoutInflater.from(MainActivity.this);

        // 初始化测试数据
        initData();
        final HorizontalScrollView scrollView = (HorizontalScrollView) findViewById(R.id.scroll);
        final Button button = (Button) findViewById(R.id.btn);
        final ImageView imageView = (ImageView) findViewById(R.id.image);
        android.support.v4.view.ViewPager pager = (ViewPager) findViewById(R.id.viewpager);
        // 设置监听
        pager.setOnPageChangeListener(new OnPageChangeListener() {

            @Override
            public void onPageSelected(int position) {
                int w = imageView.getWidth();
                // 动画类
                TranslateAnimation animation = new TranslateAnimation(
                        state * w, position * w, 0, 0);
                // 设置动画时间
                animation.setDuration(100);
                // 设置动画后保持位置
                animation.setFillAfter(true);
                imageView.setAnimation(animation);
                state = position;
                // 使HorizontalScrollView可以自动滑动(可以不要)
                if (scrollView.getScrollX() == 0 && position == 3) {
                    scrollView.scrollBy(button.getWidth(), 0);
                }
                if (scrollView.getScrollX() != 0 && position == 2) {
                    scrollView.scrollBy(-button.getWidth(), 0);
                }
                // 添加下面代码就可以让滑块在HorizontalScrollView中滑动
                scrollView.scrollBy(1, 0);
                scrollView.scrollBy(-1, 0);
            }

            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {

            }

            @Override
            public void onPageScrollStateChanged(int arg0) {

            }
        });
        pager.setAdapter(adapter);

    }

    /**
     * 初始化测试数据
     */
    private void initData() {
        for (int i = 0; i < 6; i++) {
            View view = inflater.inflate(R.layout.view, null);
            list.add(view);
        }
    }

    /**
     * viewpager的适配器
     */
    private PagerAdapter adapter = new PagerAdapter() {

        @Override
        public boolean isViewFromObject(View arg0, Object arg1) {
            return arg0 == arg1;
        }

        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            container.addView(list.get(position));
            return list.get(position);
        }

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

        }

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

}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <HorizontalScrollView
        android:id="@+id/scroll"
        android:layout_width="300dp"
        android:layout_height="wrap_content"
        android:scrollbars="none" >

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical" >

            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="50dp"
                android:orientation="horizontal" >

                <Button
                    android:id="@+id/btn"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="1" />

                <Button
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="2" />

                <Button
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="3" />

                <Button
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="4" />

                <Button
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="5" />

               
            </LinearLayout>

            <ImageView
                android:id="@+id/image"
                android:layout_width="65dp"
                android:layout_height="2dp"
                android:background="#0000ff" />
        </LinearLayout>
    </HorizontalScrollView>

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="#ffffff" >
    </android.support.v4.view.ViewPager>

</LinearLayout>