android - Cover Flow 功能使用 view pager android

Question

我必须在我的应用程序中实现封面流程功能，类似于 mobikwik app cover flow

和 .

我已经尝试过 Android CoverFlow widget library和其他一些人。但没有按预期工作。

如何使用 ViewPager 实现这种类型的 View ？

Answer 1

我已经创建了我的类 ZoomOutPageTransformer，它正在实现 PageTransformer 并使用 setPageTransformer() 方法将其设置到寻呼机中。 请检查下面的 ZoomOutPageTransformer.class -

public class ZoomOutPageTransformer implements PageTransformer {
    private static float MIN_SCALE = 1f;
    private static final float MIN_ALPHA = 0.7f;


    public ZoomOutPageTransformer(boolean isZoomEnable) {
        if (isZoomEnable) {
            MIN_SCALE = 0.85f;
        } else {
            MIN_SCALE = 1f;
        }
    }

    public void transformPage(View view, float position) {
        int pageWidth = view.getWidth();
        int pageHeight = view.getHeight();
        float vertMargin = pageHeight * (1 - MIN_SCALE) / 2;
        float horzMargin = pageWidth * (1 - MIN_SCALE) / 2;
        view.setScaleX(MIN_SCALE);
        view.setScaleY(MIN_SCALE);
        if (position < -1) { // [-Infinity,-1)
            // This page is way off-screen to the left.
            view.setAlpha(MIN_ALPHA);
            view.setTranslationX(horzMargin - vertMargin / 2);


        } else if (position <= 1) { // [-1,1]
            // Modify the default slide transition to shrink the page as well
            float scaleFactor = Math.max(MIN_SCALE, 1 - Math.abs(position));
            vertMargin = pageHeight * (1 - scaleFactor) / 2;
            horzMargin = pageWidth * (1 - scaleFactor) / 2;
            if (position < 0) {
                view.setTranslationX(horzMargin - vertMargin / 2);
            } else {
                view.setTranslationX(-horzMargin + vertMargin / 2);
            }

            // Scale the page down (between MIN_SCALE and 1)
            view.setScaleX(scaleFactor);
            view.setScaleY(scaleFactor);

            // Fade the page relative to its size.
            view.setAlpha(MIN_ALPHA +
                    (scaleFactor - MIN_SCALE) /
                            (1 - MIN_SCALE) * (1 - MIN_ALPHA));

        } else { // (1,+Infinity]
            // This page is way off-screen to the right.
            view.setAlpha(MIN_ALPHA);
            view.setTranslationX(-horzMargin + vertMargin / 2);

        }
    }
}

在 PagerActivity.java 中 -

public class PagerActivity extends Activity {

    ViewPager pager;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        pager = (ViewPager) findViewById(R.id.viewPager);
//        mContainer.setViewPager(pager);
        PagerAdapter adapter = new MyPagerAdapter();
        pager.setPageTransformer(true, new ZoomOutPageTransformer(true));
        pager.setAdapter(adapter);
        //Necessary or the pager will only have one extra page to show
        // make this at least however many pages you can see
//        pager.setOffscreenPageLimit(adapter.getCount());
        pager.setOffscreenPageLimit(3);
        //A little space between pages
        pager.setPageMargin((int) getResources().getDimension(R.dimen.dimen_20));
        //If hardware acceleration is enabled, you should also remove
        // clipping on the pager for its children.
        pager.setClipChildren(false);
    }
    //Nothing special about this adapter, just throwing up colored views for demo
    private class MyPagerAdapter extends PagerAdapter {
        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            TextView view = new TextView(PagerActivity.this);
            view.setText("Item " + position);
            view.setGravity(Gravity.CENTER);
            view.setBackgroundColor(Color.argb(255, position * 50, position * 10, position * 50));
            container.addView(view);
            return view;
        }
        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            container.removeView((View) object);
        }
        @Override
        public int getCount() {
            return 9;
        }
        @Override
        public boolean isViewFromObject(View view, Object object) {
            return (view == object);
        }
    }
}

在 main.xml 中 -

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <FrameLayout
        android:id="@+id/pager_container"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:background="#CCC"
        android:clipChildren="false">
        <android.support.v4.view.ViewPager
            android:id="@+id/viewPager"
            android:clipChildren="false"
            android:layout_width="match_parent"
            android:layout_height="300dp"
            android:layout_gravity="center"
            android:layout_marginLeft="@dimen/dimen_50"
            android:layout_marginRight="@dimen/dimen_50" />
    </FrameLayout>
</RelativeLayout>

它对我有用。