我正在尝试从我的Fragment position 0处ViewPager审核NullPointerException，我认为我已经做好了一切，但我仍然得到MainActivity
在我的Fragment我尝试使用代码检索GaitDistribution gaitDistribution = (GaitDistribution) getSupportFragmentManager().findFragmentByTag("android:switcher:" + R.id.topPager + ":" + 0);
：
FragmentPagerAdapater快速查看private static String makeFragmentName(int viewId, long id) {
return "android:switcher:" + viewId + ":" + id;
}
类告诉我们适配器为它所拥有的每个片段创建片段标记：
viewID R.id.topPager参数是viewId，但无论如何我还是试着看看FragmentPagerAdapter真正传递了什么，所以我在@Override
public Object instantiateItem(ViewGroup container, int position) {
Log.d("TAG", container.getId() + " pos: " + position);
return super.instantiateItem(container, position);
}
类中尝试了这个
2131493099 Logcat给了我viewId作为R.id.topPager，并将该整数放在标记字符串而不是public class MyHorseViewPagerAdapter extends FragmentPagerAdapter {
private static final int NUMofPages = 3;
private int walkProgess, canterProgress, trotProgress;
private int duration;
private boolean isSound, isVibrate;
public MyHorseViewPagerAdapter(FragmentManager fm, int walkProgess, int canterProgress, int trotProgress, int duration, boolean isSound, boolean isVibrate) {
super(fm);
this.walkProgess = walkProgess;
this.canterProgress = canterProgress;
this.trotProgress = trotProgress;
this.duration = duration;
this.isSound = isSound;
this.isVibrate = isVibrate;
}
public MyHorseViewPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
switch (position) {
case 0:
GaitDistribution gaitDistribution = GaitDistribution.newInstance(walkProgess, trotProgress, canterProgress, isSound, isVibrate, duration);
return gaitDistribution;
case 1:
Intensity intensity = new Intensity();
intensity.setRetainInstance(true);
return intensity;
case 2:
Stats stats = new Stats();
return stats;
default:
return null;
}
}
@Override
public int getCount() {
return NUMofPages;
}
}
中，但没有成功！
ViewPager适配器：
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Switch(position) {
case 0:
//get first subcategories array values
break;
case 1:
//get second subcategories array values
break;
....
}
}