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>