我开发了一种滚动机制来选择应用程序中的人员.它是自定义视图寻呼机,允许每次在屏幕上显示多个项目(在我的情况下为3),并且两侧都有阴影.
以下是它在Nexus 5,Nexus 4,Galaxy S3等设备上的外观和工作原理:
但在某些设备上(索尼Xperia和不同类型的摩托罗拉),渲染看起来很糟糕,结果如下:
关于代码,我参考了@Commonsware的这篇博文:
http://commonsware.com/blog/2012/08/20/multiple-view-viewpager-options.html
这是我的相关代码:
PagerContainer:
public class PagerContainer extends FrameLayout implements ViewPager.OnPageChangeListener { private ViewPager mPager; boolean mNeedsRedraw = false; public PagerContainer(Context context) { super(context); init(); } public PagerContainer(Context context,AttributeSet attrs) { super(context,attrs); init(); } public PagerContainer(Context context,AttributeSet attrs,int defStyle) { super(context,attrs,defStyle); init(); } private void init() { //Disable clipping of children so non-selected pages are visible setClipChildren(false); //Child clipping doesn't work with hardware acceleration in Android 3.x/4.x //You need to set this value here if using hardware acceleration in an // application targeted at these releases. if (Build.VERSION.SDK_INT >= 11 && Build.VERSION.SDK_INT < 19) { setLayerType(View.LAYER_TYPE_SOFTWARE,null); } } @Override protected void onFinishInflate() { try { mPager = (ViewPager) getChildAt(0); mPager.setOnPageChangeListener(this); } catch (Exception e) { throw new IllegalStateException("The root child of PagerContainer must be a ViewPager"); } } public ViewPager getViewPager() { return mPager; } private Point mCenter = new Point(); private Point mInitialTouch = new Point(); @Override protected void onSizeChanged(int w,int h,int oldw,int oldh) { mCenter.x = w / 2; mCenter.y = h / 2; } @Override public boolean onTouchEvent(MotionEvent ev) { //We capture any touches not already handled by the ViewPager // to implement scrolling from a touch outside the pager bounds. switch (ev.getAction()) { case MotionEvent.ACTION_DOWN: mInitialTouch.x = (int)ev.getX(); mInitialTouch.y = (int)ev.getY(); default: ev.offsetLocation(mCenter.x - mInitialTouch.x,mCenter.y - mInitialTouch.y); break; } return mPager.dispatchTouchEvent(ev); } @Override public void onPageScrolled(int position,float positionOffset,int positionOffsetPixels) { //Force the container to redraw on scrolling. //Without this the outer pages render initially and then stay static if (mNeedsRedraw) invalidate(); } @Override public void onPageSelected(int position) { invalidate(); } @Override public void onPageScrollStateChanged(int state) { mNeedsRedraw = (state != ViewPager.SCROLL_STATE_IDLE); } }
初始部分:
//Size View Pager: //======================================== pagerSize = mContainerSize.getViewPager(); adapter = new MySizePagerAdapter(); pagerSize.setAdapter(adapter); //Necessary or the pager will only have one extra page to show make this at least however many pages you can see pagerSize.setOffscreenPageLimit(adapter.getCount()); //A little space between pages pagerSize.setPageMargin(15); //If hardware acceleration is enabled,you should also remove clipping on the pager for its children. pagerSize.setClipChildren(false);
更多的研究让我明白这个问题与硬件加速或某些设备缺乏硬件加速有关.但是通过代码禁用它也没有帮助我.
解决方法
我会尝试将ViewPager的layerType设置为软件渲染,而不是父框架布局.
您也可以查看此博文:http://udinic.wordpress.com/2013/09/16/viewpager-and-hardware-acceleration/