ViewPager中间大两边小效果的实现

来源：互联网发布：怎样优化limit 分页编辑：程序博客网时间：2024/04/19 00:08

Activity部分：

public class MainActivity extends Activity {    private ViewPager mViewPager;    private ViewPaperAdapter mVpAdapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mViewPager = (ViewPager) this.findViewById(R.id.viewpager);        List<Integer> imageIds = new ArrayList<Integer>();        imageIds.add(R.drawable.image01);        imageIds.add(R.drawable.image02);        imageIds.add(R.drawable.image03);        mVpAdapter = new ViewPaperAdapter(this, imageIds);        mViewPager.setOffscreenPageLimit(3);        mViewPager.setAdapter(mVpAdapter);//      这个值主要负责两边控件与中间控件的距离        mViewPager.setPageMargin(-300);        mViewPager.setPageTransformer(false, new DepthPageTransformer());    }}

适配器部分:

public class ViewPaperAdapter extends PagerAdapter {    private Context mContext;    private List<Integer> mImageIds;    /**     * @param mainActivity     * @param integers     */    public ViewPaperAdapter(Context context, List<Integer> imageIds) {        this.mContext = context;        this.mImageIds = imageIds;    }    @Override    public int getCount() {        return this.mImageIds.size();    }    @Override    public boolean isViewFromObject(View arg0, Object arg1) {        return arg0 == arg1;    }    @Override    public void destroyItem(View container, int position, Object object) {        ((ViewPager) container).removeView((View) object);    }    @Override    public Object instantiateItem(View container, int position) {        ImageView image=new ImageView(mContext);        image.setImageResource(mImageIds.get(position));        image.setScaleType(ScaleType.FIT_XY);        image.setPadding(200, 80, 200, 80);        ((ViewPager) container).addView(image);        return image;    }}

效果部分：

@TargetApi(Build.VERSION_CODES.HONEYCOMB)public class DepthPageTransformer implements PageTransformer {    private static final float MIN_SCALE = 0.5f;    private static final float MIN_ALPHA = 0.8f;    @TargetApi(Build.VERSION_CODES.HONEYCOMB)    @SuppressLint("NewApi")    public void transformPage(View view, float position) {        if (position < -1) { // [-Infinity,-1)            // This page is way off-screen to the left.            view.setScaleY(MIN_SCALE);            view.setAlpha(MIN_ALPHA);        } else if (position == 0) { // [-1,0]            // Use the default slide transition when moving to the left page            view.setScaleY(MIN_SCALE);            view.setAlpha(MIN_ALPHA);        } else if (position <= 1) { // (0,1]            // Fade the page out.            // Counteract the default slide transition            // Scale the page down (between MIN_SCALE and 1)            float scaleFactor = MIN_SCALE + (1 - MIN_SCALE)* (1 - Math.abs(position));            float alphaFactor = MIN_ALPHA + (1 - MIN_ALPHA)* (1 - Math.abs(position));            view.setScaleY(scaleFactor);            view.setAlpha(alphaFactor);        } else { // (1,+Infinity]            // This page is way off-screen to the right.            view.setScaleY(MIN_SCALE);            view.setAlpha(MIN_ALPHA);        }    }}

xml布局:

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="#ffff00"    android:orientation="vertical" >    <android.support.v4.view.ViewPager        android:id="@+id/viewpager"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:paddingLeft="100dp"        android:paddingRight="100dp" /></LinearLayout>

0 0