我已经实现了垂直viewpager和水平viewpager单独的类。现在我试图将水平viewpager放在垂直viewpager中。但我得到了nullpointer异常
这里返回水平viewpager的方法
public ViewPager getViewPager()
{
LayoutInflater inflater = (LayoutInflater)getSystemService
(Context.LAYOUT_INFLATER_SERVICE);
View rootView = inflater.inflate(R.layout.swipe_item, null, true);
android.support.v4.view.ViewPager pag = (android.support.v4.view.ViewPager)rootView.findViewById(R.id.pager);
mDemoCollectionPagerAdapter = new DemoCollectionPagerAdapter(getSupportFragmentManager());
pag.setAdapter(mDemoCollectionPagerAdapter);
return pag ;
}
这里是垂直视图寻呼机我试图放置水平viewpager
VerticalItem item = new VerticalItem();
ViewPager pag = item.getViewPager();
mViewPager = (VerticalPager) findViewById(R.id.pager);
mViewPager.addView(pag);
mViewPager.setTag(0);
这两个类都是fragmentactivity的子类
这是我的日志猫
06-01 10：25：59.468：E / AndroidRuntime（2128）：致命异议：主要
06-01 10：25：59.468：E / AndroidRuntime（2128）：java.lang.RuntimeException：无法启动活动ComponentInfo {com.example.infogamma / com.example.infogamma.CollectionDemoActivity}：java.lang.IllegalStateException：System onCreate（）之前不可用于活动的服务 06-01 10：25：59.468：E / AndroidRuntime（2128）：在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2211）
06-01 10：25：59.468：E / AndroidRuntime（2128）：在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2261）
06-01 10：25：59.468：E / AndroidRuntime（2128）：在android.app.ActivityThread.access $ 600（ActivityThread.java:141）
06-01 10：25：59.468：E / AndroidRuntime（2128）：在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1256）
06-01 10：25：59.468：E / AndroidRuntime（2128）：在android.os.Handler.dispatchMessage（Handler.java:99）
06-01 10：25：59.468：E / AndroidRuntime（2128）：在android.os.Looper.loop（Looper.java:137）
06-01 10：25：59.468：E / AndroidRuntime（2128）：在android.app.ActivityThread.main（ActivityThread.java:5103）
06-01 10：25：59.468：E / AndroidRuntime（2128）：at java.lang.reflect.Method.invokeNative（Native Method）
06-01 10：25：59.468：E / AndroidRuntime（2128）：at java.lang.reflect.Method.invoke（Method.java:525)
06-01 10：25：59.468：E / AndroidRuntime（2128）：at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:737)
06-01 10：25：59.468：E / AndroidRuntime（2128）：at com.android.internal.os.ZygoteInit.main（ZygoteInit.java:553）
06-01 10：25：59.468：E / AndroidRuntime（2128）：at dalvik.system.NativeStart.main（Native Method）
06-01 10：25：59.468：E / AndroidRuntime（2128）：引起：java.lang.IllegalStateException：onCreate（）之前活动不可用的系统服务
06-01 10：25：59.468：E / AndroidRuntime（2128）：在android.app.Activity.getSystemService（Activity.java:4492）
06-01 10：25：59.468：E / AndroidRuntime（2128）：at com.example.infogamma.VerticalItem.getViewPager（VerticalItem.java:151)
06-01 10：25：59.468：E / AndroidRuntime（2128）：at com.example.infogamma.CollectionDemoActivity.onCreate（CollectionDemoActivity.java:63）
06-01 10：25：59.468：E / AndroidRuntime（2128）：在android.app.Activity.performCreate（Activity.java:5133）
06-01 10：25：59.468：E / AndroidRuntime（2128）：在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1087）
06-01 10：25：59.468：E / AndroidRuntime（2128）：在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2175）
06-01 10：25：59.468：E / AndroidRuntime（2128）：... 11更多
这是我的collectiondemoactivity
public class CollectionDemoActivity extends FragmentActivity {
DemoCollectionPagerAdapter mDemoCollectionPagerAdapter;
static String[] screens= {"makescr1","makescr2","makescr3"};
/**
* The {@link android.support.v4.view.ViewPager} that will display the object collection.
*/
VerticalPager mViewPager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.full_image);
LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
//ViewGroup fl = (ViewGroup)findViewById(R.layout.full_image);
View rootView = inflater.inflate(R.layout.swipe_item, null, false);
android.support.v4.view.ViewPager pag = (android.support.v4.view.ViewPager)rootView.findViewById(R.id.pager);
VerticalItem item = new VerticalItem();
pag = item.getViewPager();
final ActionBar actionBar = getActionBar();
actionBar.hide();
//ViewPager vp.item.getViewPager();
// Set up the ViewPager, attaching the adapter.
mViewPager = (VerticalPager) findViewById(R.id.pager);
//mViewPager.setHorizontalScrollBarEnabled(true);
mViewPager.addView(pag);
mViewPager.setTag(0);
}
这是我的verticalitem类
public class VerticalItem extends FragmentActivity {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide fragments representing
* each object in a collection. We use a {@link android.support.v4.app.FragmentStatePagerAdapter}
* derivative, which will destroy and re-create fragments as needed, saving and restoring their
* state in the process. This is important to conserve memory and is a best practice when
* allowing navigation between objects in a potentially large collection.
*/
DemoCollectionPagerAdapter mDemoCollectionPagerAdapter;
static String[] screens= {"makescr1","makescr2","makescr3"};
/**
* The {@link android.support.v4.view.ViewPager} that will display the object collection.
*/
VerticalPager mViewPager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.full_image);
}
public ViewPager getViewPager()
{
LayoutInflater inflater = (LayoutInflater)getSystemService
(Context.LAYOUT_INFLATER_SERVICE);
View rootView = inflater.inflate(R.layout.swipe_item, null, true);
android.support.v4.view.ViewPager pag = (android.support.v4.view.ViewPager)rootView.findViewById(R.id.pager);
mDemoCollectionPagerAdapter = new DemoCollectionPagerAdapter(getSupportFragmentManager());
pag.setAdapter(mDemoCollectionPagerAdapter);
return pag ;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// This is called when the Home (Up) button is pressed in the action bar.
// Create a simple intent that starts the hierarchical parent activity and
// use NavUtils in the Support Package to ensure proper handling of Up.
Intent upIntent = new Intent(this, MainActivity.class);
if (NavUtils.shouldUpRecreateTask(this, upIntent)) {
// This activity is not part of the application's task, so create a new task
// with a synthesized back stack.
/* TaskStackBuilder.from(this)
// If there are ancestor activities, they should be added here.
.addNextIntent(upIntent)
.startActivities();
finish();*/
} else {
// This activity is part of the application's task, so simply
// navigate up to the hierarchical parent activity.
NavUtils.navigateUpTo(this, upIntent);
}
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A {@link android.support.v4.app.FragmentStatePagerAdapter} that returns a fragment
* representing an object in the collection.
*/
public static class DemoCollectionPagerAdapter extends FragmentStatePagerAdapter {
public DemoCollectionPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int i) {
Fragment fragment = new DemoObjectFragment();
Bundle args = new Bundle();
args.putInt(DemoObjectFragment.ARG_OBJECT, i + 1); // Our object is just an integer :-P
args.putString("scr",screens[i]);
fragment.setArguments(args);
return fragment;
}
@Override
public int getCount() {
// For this contrived example, we have a 100-object collection.
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
return "OBJECT " + (position + 1);
}
}
/**
* A dummy fragment representing a section of the app, but that simply displays dummy text.
*/
public static class DemoObjectFragment extends Fragment {
public static final String ARG_OBJECT = "object";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_collection_object, container, false);
Bundle args = getArguments();
ImageView img = (ImageView)rootView.findViewById(R.id.screen);
int resId = getResources().getIdentifier(args.getString("scr"), "drawable", "com.example.infogamma");
img.setImageResource(resId);
//getActivity().getSupportFragmentManager().beginTransaction().remove(this).commit();
//rootView.setRotation(-90f);
return rootView;
}
}
}
答案 0 :(得分：0)
你对root视图有空，你说是附加到root：
查看rootView = inflater.inflate（R.layout.swipe_item，null，true）;
要么给它一个rootView，要么使其成为真假