【原创】android ViewPager控件的使用
android4.0有个控件，就是viewpager，用来实现左右滑动效果的。我们具体来看看是如何使用的。
首先看一下效果图
3个tab，每个tab有个layout，滑动的时候指示滑动条跟着走（当然，我觉得这个滑动条可以用三张图片来实现，更简单点）。
具体的我们看代码吧，主页xml就是实现上面三个tabbar，滑动条和一个viewpager控件，如下：
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <LinearLayout android:id="@+id/linearLayout1" android:layout_width="fill_parent" android:layout_height="100.0dip" android:background="#FFFFFF" > <TextView android:id="@+id/text1" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" android:gravity="center" android:text="页卡1" android:textColor="#000000" android:textSize="22.0dip" /> <TextView android:id="@+id/text2" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" android:gravity="center" android:text="页卡2" android:textColor="#000000" android:textSize="22.0dip" /> <TextView android:id="@+id/text3" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1.0" android:gravity="center" android:text="页卡3" android:textColor="#000000" android:textSize="22.0dip" /> </LinearLayout> <ImageView android:id="@+id/cursor" android:layout_width="fill_parent" android:layout_height="wrap_content" android:scaleType="matrix" android:src="@drawable/slide" /> <android.support.v4.view.ViewPager android:id="@+id/vPager" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_weight="1.0" android:background="#000000" android:flipInterval="30" android:persistentDrawingCache="animation" /></LinearLayout>
public class ViewPageDemoActivity extends Activity {private ViewPager mPager;// 页卡内容private List<View> listViews; // Tab页面列表private ImageView cursor;// 动画图片private TextView t1, t2, t3;// 页卡头标private int offset = 0;// 动画图片偏移量private int currIndex = 0;// 当前页卡编号private int bmpW;// 动画图片宽度MyPagerAdapter adapter;LayoutInflater mInflater;/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);Log.i("Viewpage","--onCreate--");initImageView();initTextView();initPageView();}private void initPageView() {mInflater = getLayoutInflater();listViews = new ArrayList<View>();listViews.add(mInflater.inflate(R.layout.item1, null));listViews.add(mInflater.inflate(R.layout.item2, null));listViews.add(mInflater.inflate(R.layout.item3, null));adapter = new MyPagerAdapter(listViews);mPager = (ViewPager) findViewById(R.id.vPager);mPager.setAdapter(adapter);mPager.setCurrentItem(0);mPager.setOnPageChangeListener(new MyOnPageChangeListener());}private void initTextView() {t1 = (TextView) findViewById(R.id.text1);t2 = (TextView) findViewById(R.id.text2);t3 = (TextView) findViewById(R.id.text3);t1.setOnClickListener(new MyOnClickListener(0));t2.setOnClickListener(new MyOnClickListener(1));t3.setOnClickListener(new MyOnClickListener(2));}private void initImageView() {cursor = (ImageView) findViewById(R.id.cursor);bmpW = BitmapFactory.decodeResource(getResources(), R.drawable.slide).getWidth();// 获取图片宽度DisplayMetrics dm = new DisplayMetrics();getWindowManager().getDefaultDisplay().getMetrics(dm);int screenW = dm.widthPixels;// 获取分辨率宽度offset = (screenW / 3 - bmpW) / 2;// 计算偏移量Matrix matrix = new Matrix();matrix.postTranslate(offset, 0);cursor.setImageMatrix(matrix);// 设置动画初始位置}private class MyOnClickListener implements View.OnClickListener {private int index = 0;public MyOnClickListener(int i) {index = i;}@Overridepublic void onClick(View v) {// TODO Auto-generated method stubmPager.setCurrentItem(index);}}public class MyPagerAdapter extends PagerAdapter {public List<View> mListViews;public MyPagerAdapter(List<View> mListViews) {this.mListViews = mListViews;}public void destroyItem(View arg0, int arg1, Object arg2) {((ViewPager) arg0).removeView(mListViews.get(arg1));}public void finishUpdate(View arg0) {}@Overridepublic int getCount() {return mListViews.size();}@Overridepublic Object instantiateItem(View arg0, int arg1) {((ViewPager) arg0).addView(mListViews.get(arg1), 0);return mListViews.get(arg1);}@Overridepublic boolean isViewFromObject(View arg0, Object arg1) {return arg0 == (arg1);}@Overridepublic void restoreState(Parcelable arg0, ClassLoader arg1) {}@Overridepublic Parcelable saveState() {return null;}@Overridepublic void startUpdate(View arg0) {}}public class MyOnPageChangeListener implements OnPageChangeListener {int one = offset * 2 + bmpW;// 页卡1 -> 页卡2 偏移量int two = one * 2;// 页卡1 -> 页卡3 偏移量@Overridepublic void onPageSelected(int arg0) {Animation animation = null;switch (arg0) {case 0:if (currIndex == 1) {animation = new TranslateAnimation(one, 0, 0, 0);} else if (currIndex == 2) {animation = new TranslateAnimation(two, 0, 0, 0);}break;case 1:if (currIndex == 0) {animation = new TranslateAnimation(offset, one, 0, 0);} else if (currIndex == 2) {animation = new TranslateAnimation(two, one, 0, 0);}break;case 2:if (currIndex == 0) {animation = new TranslateAnimation(offset, two, 0, 0);} else if (currIndex == 1) {animation = new TranslateAnimation(one, two, 0, 0);}break;}currIndex = arg0;animation.setFillAfter(true);// True:图片停在动画结束位置animation.setDuration(300);cursor.startAnimation(animation);}@Overridepublic void onPageScrolled(int arg0, float arg1, int arg2) {}@Overridepublic void onPageScrollStateChanged(int arg0) {}}}