ViewPager已经有了滑动的功能
activity_main.xml
<?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:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.lemon.viewpagerdemo.MainActivity"> <android.support.v4.view.ViewPager
android:id="@+id/main_viewpager"
android:layout_width="wrap_content"
android:layout_height="wrap_content"> </android.support.v4.view.ViewPager>
</LinearLayout>
MainActivity.java
public class MainActivity extends AppCompatActivity {
private ViewPager mViewPager;
private int[] mImgIds = new int[] { R.drawable.a,
R.drawable.b, R.drawable.c};
private List<ImageView> mImageViews = new ArrayList<ImageView>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initData();
mViewPager = (ViewPager) findViewById(R.id.main_viewpager);
mViewPager.setAdapter(new PagerAdapter(){
@Override
public Object instantiateItem(ViewGroup container, int position)
{
container.addView(mImageViews.get(position));
return mImageViews.get(position);
}
@Override
public void destroyItem(ViewGroup container, int position,
Object object)
{
container.removeView(mImageViews.get(position));
}
@Override
public boolean isViewFromObject(View view, Object object)
{
return view == object;
}
@Override
public int getCount()
{
return mImgIds.length;
}
});
//setPageTransformer(boolean reverseDrawingOrder, PageTransformer transformer)
//用于设置ViewPager切换时的动画效果
mViewPager.setPageTransformer(true,new DepthPageTransformer());
}
private void initData() {
for (int imgId : mImgIds)
{
ImageView imageView = new ImageView(getApplicationContext());
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setImageResource(imgId);
mImageViews.add(imageView);
}
}
}DepthPageTransformer.java
public class DepthPageTransformer implements ViewPager.PageTransformer{
private static final float MIN_SCALE = 0.75f;
@Override
public void transformPage(View view, float position) {
int pageWidth = view.getWidth();
if(position<-1){ // [-Infinity,-1)
view.setAlpha(0);
}else if(position<=0){// [-1,0]
view.setAlpha(1);
view.setTranslationX(0);
view.setScaleX(1);
view.setScaleY(1);
}else if(position<=1){// (0,1]
view.setAlpha(1-position);
view.setTranslationX(pageWidth*-position);
float scaleFactor = MIN_SCALE+(1-MIN_SCALE)*(1-Math.abs(position));
view.setScaleX(scaleFactor);
view.setScaleY(scaleFactor);
}else{//(1,+Infinity]
view.setAlpha(0);
}
}
}