我开发了一种滚动机制,用于选择应用程序中的员工。它的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个),并且两侧都有阴影。
以下是 Nexus 5 , Nexus 4 , Galaxy S3 等设备的外观和效果:
但是在某些设备上(索尼Xperia ,以及不同类型的摩托罗拉),渲染看起来很糟糕,结果如下:
关于我通过 @Commonsware 评论此博客文章的代码:
http://commonsware.com/blog/2012/08/20/multiple-view-viewpager-options.html
第三个选项可以找到代码here。
以下是我的相关代码:
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有关,或者在某些设备中缺少硬件加速。但是通过代码禁用它也没有帮助我。
答案 0 :(得分:2)
我会尝试将ViewPager的layerType设置为软件渲染,而不是父框架布局。
您还可以查看此博文:http://udinic.wordpress.com/2013/09/16/viewpager-and-hardware-acceleration/
答案 1 :(得分:0)
我最终使用了ViewPager
的另一个实现,它给了我相同的结果,但渲染问题无处可见,这是代码:
private class MyTypePagerAdapter extends PagerAdapter {
@Override
public Object instantiateItem(ViewGroup container, int position) {
TextView view = new TextView(getActivity());
view.setText(mTempBeverageList.get(position).getName().toUpperCase());
if (!wasTypeChanged && (!isLocaleHebrew && position == 1))
{
view.setTypeface(null, Typeface.BOLD);
view.setTextSize(19);
}
else
{
view.setTextSize(16);
}
view.setSingleLine();
view.setGravity(Gravity.CENTER);
view.setTextColor(getResources().getColor(R.color.cups_black));
view.setBackgroundColor(getResources().getColor(R.color.cups_cyan));
container.addView(view);
return view;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View)object);
}
@Override
public int getCount() {
return mTempBeverageList.size();
}
@Override
public float getPageWidth(int position) {
return (0.33333f);
}
@Override
public boolean isViewFromObject(View view, Object object) {
return (view == object);
}
}
初始化部分:
pagerType= (ViewPager) view.findViewById(R.id.pagerType);
pagerType.setAdapter(new MyTypePagerAdapter());
pagerType.setOffscreenPageLimit(6);