如何创建圆形取景器？
如何创建圆形取景器？
提问于 2012-07-13 07:15:26
我的代码中有三个片段类。FirstActivity，SecondActivity，ThirdActivity，我想刷一下这三个活动。这三个是从片段类扩展而来的。
public class ViewPagerFragmentActivity extends FragmentActivity {
private PagerAdapter mPagerAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
super.onCreate(savedInstanceState);
super.setContentView(R.layout.viewpager_layout);
initialisePaging();
}
/**
* Initialize the fragments to be paged
*/
List<Fragment> fragments = new Vector<Fragment>();
ViewPager pager;
private void initialisePaging() {
fragments.add(Fragment.instantiate(this, FirstActivity.class.getName()));
fragments.add(Fragment.instantiate(this, SecondActivity.class.getName()));
fragments.add(Fragment.instantiate(this, ThirdActivity.class.getName()));
this.mPagerAdapter = new MyPagerAdapter(super.getSupportFragmentManager(), fragments);
pager = (ViewPager) super.findViewById(R.id.viewpager);
pager.setAdapter(this.mPagerAdapter);
}}
这是我的FragmentPageAdapter课程
public class MyPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> fragments;
public MyPagerAdapter(FragmentManager fm, List<Fragment> fragments) {
super(fm);
this.fragments = fragments;
}
@Override
public Fragment getItem(int position) {
System.out.println("position"+position);
return this.fragments.get(position);
}
@Override
public int getCount() {
return this.fragments.size();
}}
我的代码是这样工作的，A<->B<->c，但我的要求是像这样运行，循环片段中的C<->A<->B<->C<-A->是可滑动的。
回答 2
Stack Overflow用户
回答已采纳
发布于 2012-07-13 10:03:46
圆形ViewPager是可能的。在ViewPager as a circular queue / wrapping的帮助下，这个链接已经这样编码了。希望它能帮到你想要的。
CircluarPagerAdapter类：
public class CircularPagerAdapter extends PagerAdapter{
private int[] pageIDsArray;
private int count;
public CircularPagerAdapter(final ViewPager pager, int... pageIDs) {
super();
int actualNoOfIDs = pageIDs.length;
count = actualNoOfIDs + 2;
pageIDsArray = new int[count];
for (int i = 0; i < actualNoOfIDs; i++) {
pageIDsArray[i + 1] = pageIDs[i];
}
pageIDsArray[0] = pageIDs[actualNoOfIDs - 1];
pageIDsArray[count - 1] = pageIDs[0];
pager.setOnPageChangeListener(new OnPageChangeListener() {
public void onPageSelected(int position) {
int pageCount = getCount();
if (position == 0){
pager.setCurrentItem(pageCount-2,false);
} else if (position == pageCount-1){
pager.setCurrentItem(1,false);
}
}
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
// TODO Auto-generated method stub
}
public void onPageScrollStateChanged(int state) {
// TODO Auto-generated method stub
}
});
}
public int getCount() {
return count;
}
public Object instantiateItem(View container, int position) {
LayoutInflater inflater = (LayoutInflater) container.getContext()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
int pageId = pageIDsArray[position];
View view = inflater.inflate(pageId, null);
((ViewPager) container).addView(view, 0);
return view;
}
@Override
public void destroyItem(View container, int position, Object object) {
((ViewPager) container).removeView((View) object);
}
@Override
public void finishUpdate(View container) {
// TODO Auto-generated method stub
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == ((View) object);
}
@Override
public void restoreState(Parcelable state, ClassLoader loader) {
// TODO Auto-generated method stub
}
@Override
public Parcelable saveState() {
// TODO Auto-generated method stub
return null;
}
@Override
public void startUpdate(View container) {
// TODO Auto-generated method stub
}
}这是你的主要课程：
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ViewPager myPager = (ViewPager) findViewById(R.id.conpageslider);
PagerAdapter adapter = new CircularPagerAdapter(myPager, new int[]{R.layout.first_activity, R.layout.second_activity, R.layout.third_activity});
myPager.setAdapter(adapter);
myPager.setCurrentItem(3);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}Stack Overflow用户
发布于 2012-07-13 07:45:18
你可以试试这样的东西：
1)使getCount()返回一个巨大的值(比用户可能使用的值高出许多)
2)让getItem返回这样的东西。
3)让您的寻呼机开始在getCount()定义的范围的中间(允许从A到C在开始时滑动)，确保选择一个值，该值将为您提供第一个片段%3
我知道这个解决方案看上去有点脏，但我目前找不到更好的解决办法
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/11465815
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