在ViewPager的特定页面中更改ImageView源代码Android
问题描述:
我想要在查看传呼机中的特定页面中更改imageresource。这就是我所做的。在ViewPager的特定页面中更改ImageView源代码Android
这是活动的onCreate ...
((PlaceholderFragment)mSectionsPagerAdapter.getItem(0)).updateImage(R.drawable.help1);
((PlaceholderFragment)mSectionsPagerAdapter.getItem(1)).updateImage(R.drawable.help2);
((PlaceholderFragment)mSectionsPagerAdapter.getItem(2)).updateImage(R.drawable.help3);
((PlaceholderFragment)mSectionsPagerAdapter.getItem(3)).updateImage(R.drawable.help4);
这是片段类...
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_help, container, false);
ImageView imageView = (ImageView) rootView.findViewById(R.id.imageHelp);
imageView.setImageResource(R.drawable.help4);
return rootView;
}
public void updateImage(int image){
ImageView imageView = (ImageView) getView().findViewById(R.id.imageHelp);
imageView.setImageResource(image);
}
}
但不知何故,它仍然给我错误空指针异常。我怎么错过? 以前感谢,请帮助我:)我在这里停留了大约2个小时。
答
// declare rootView as global variable
public void updateImage(int image){
ImageView imageView = (ImageView) rootView.findViewById(R.id.imageHelp);
imageView.setImageResource(rootView);
}
+0
我这样做,使rootView全局,但不知何故它仍然给我的错误引起:java.lang.NullPointerException:尝试调用虚拟方法'android.view.View android.view.View.findViewById(int)'on空对象引用 – user2565280 2015-01-22 00:54:11
+0
请提供一些更多的澄清代码 – koutuk 2015-01-22 05:35:42
显示您的logcat以及显示空指针异常的哪一行。 – duggu 2015-01-21 13:08:10
引起︰java.lang.NullPointerException︰尝试调用空对象引用虚拟方法'android.view.View android.view.View.findViewById(int)' 原因由行ImageView imageView =(ImageView)rootView。 .. – user2565280 2015-01-22 00:52:42