如何在视图寻呼机中find“最后一页”。 或视图的总“数量”。 Android开发

感谢您的高级帮助。 抱歉,如果这是一个非常愚蠢的问题,但我无法在其他地方find它。 基本上,我想要的是确定我在ViewPager中设置的页面总数,就像在我的代码中一样。 我已经尝试(在更高版本中)将“sizevariables”添加到f作为它的参数(参见FirstFragment)。 这不是一个已知的数字,因为用户输入我将创建的表单(视图)的数量,并将其作为意图传递给FirstFragment。 所以我试过了:

Fragment f = new UserFragment(); Bundle bundl = new Bundle(); bundl.putInt("pagenumbers", size); f.setArguments(bundl); lf.add(f); 

在FirstFragment中。 但是当UserFragment在“pagenumbers”下提取它的参数时,它返回0.然后我试图访问存在于FragmentAdapter中的getCount()方法,但是,我不知道如何解决这个问题,因为我是在我需要它的时候在UserFragment里面。

我正在尝试做些什么可能有助于澄清,我正在提取“当前页面信息”,我现在已经工作了,感谢我的早期post和那些帮助过的人。 现在我想查看“currentpage == size(//是页数。在viewpager中的总视图数”)。 因此,在onClick方法中,您可以在UserFragment中看到,如果它是最后一页,则用户点击按钮转到下一页。 我希望它跳转到另一个活动,它操作从所有表单收集的所有SparseArray数据。 (我需要有关如何将此SparseArray数据放入intent中的帮助,我可能会对此提出一个新问题……因为它不是很相关)。 所以,如果你可以帮助我获得当前的工作尝试(如何正确地做到这一点),或者只是建议一种全新的方法,我很高兴。 只要我能让它工作!

非常感谢您提供的所有帮助。 请帮忙!

我的UserFragment.java

  package com.example.thinice; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.view.ViewPager; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnClickListener; import android.view.ViewGroup; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; public class UserFragment extends Fragment { public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.layout_avgcalcform, container, false); final EditText markc = (EditText)rootView.findViewById(R.id.editTextASSMARK); final EditText marktotc = (EditText)rootView.findViewById(R.id.editTextASSTOT); final EditText assvalc = (EditText)rootView.findViewById(R.id.editTextASSWORTH); int currentviewnum = ((FirstFragment) getActivity()).getPager().getCurrentItem(); String pagenum = Integer.toString(currentviewnum); TextView tv = (TextView) rootView.findViewById(R.id.avg_testtv); tv.setText(pagenum); Button b = (Button) rootView.findViewById(R.id.button1); b.setOnClickListener( new View.OnClickListener(){ public void onClick(View v){ int currentviewnum = ((FirstFragment) getActivity()).getPager().getCurrentItem(); ((FirstFragment) getActivity()).saveData(new Question(markc.getText().toString(),marktotc.getText().toString(),assvalc.getText().toString())); ((FirstFragment) getActivity()).getPager().setCurrentItem(currentviewnum+1); } }); return rootView; } } 

如果您需要查看我的更多代码,请告诉我。 但这真让我烦恼。 所以,如果有人可以帮助我,那就太棒了! 非常感谢你的进步。

FragmentAdapter.java

  package com.example.thinice; import java.util.ArrayList; import java.util.List; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentPagerAdapter; import android.view.ViewGroup; public class FragmentAdapter extends FragmentPagerAdapter{ private List fragments; public FragmentAdapter(FragmentManager fragmentManager, ArrayList fragments) { super(fragmentManager); this.fragments = fragments; } @Override public Fragment getItem(int position) { //Bundle args = new Bundle(); //args.putInt("page_position", position+1); //((Fragment) fragments).setArguments(args); return this.fragments.get(position); } @Override public void destroyItem (ViewGroup container, int position, Object object) { super.destroyItem(container, position, object); } @Override public int getCount() { return this.fragments.size(); } } 

FirstFragment.java(这是我的活动)

  package com.example.thinice; import java.util.ArrayList; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentActivity; import android.support.v4.view.ViewPager; import android.util.SparseArray; import android.widget.Button; public class FirstFragment extends FragmentActivity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.layout_viewpager); // Check whether the activity is using the layout version with // the fragment_container FrameLayout. If so, we must add the first fragment int size = getIntent().getExtras().getInt("numass1"); ViewPager vp = (ViewPager) findViewById(R.id.viewPager); if (savedInstanceState != null) { return; } ArrayList lf = new ArrayList(); for(int count=0; count<size; count ++){ Fragment f = new UserFragment(); lf.add(f); } FragmentAdapter hello = new FragmentAdapter(getSupportFragmentManager() , lf); vp.setAdapter(hello); // vp.setOffscreenPageLimit(size); } SparseArray questions = new SparseArray(); public void saveData(Question quest){ ViewPager vp = (ViewPager) findViewById(R.id.viewPager); questions.put(vp.getCurrentItem(), quest); } public ViewPager getPager() { ViewPager vp = (ViewPager) findViewById(R.id.viewPager); return vp; } } 

编辑:建议解决方案的LOGCAT文件

 07-06 20:51:50.241: D/AndroidRuntime(8151): Shutting down VM 07-06 20:51:50.241: W/dalvikvm(8151): threadid=1: thread exiting with uncaught exception (group=0x415a4ba8) 07-06 20:51:50.251: E/AndroidRuntime(8151): FATAL EXCEPTION: main 07-06 20:51:50.251: E/AndroidRuntime(8151): Process: com.example.thinice, PID: 8151 07-06 20:51:50.251: E/AndroidRuntime(8151): java.lang.NullPointerException 07-06 20:51:50.251: E/AndroidRuntime(8151): at com.example.thinice.UserFragment.onCreateView(UserFragment.java:34) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.support.v4.app.Fragment.performCreateView(Fragment.java:1500) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:927) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:472) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.support.v4.view.ViewPager.populate(ViewPager.java:1068) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.support.v4.view.ViewPager.populate(ViewPager.java:914) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1436) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.View.measure(View.java:16497) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.View.measure(View.java:16497) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 07-06 20:51:50.251: E/AndroidRuntime(8151): at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:327) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.View.measure(View.java:16497) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 07-06 20:51:50.251: E/AndroidRuntime(8151): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.View.measure(View.java:16497) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1912) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1109) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1291) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:996) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5600) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.Choreographer.doCallbacks(Choreographer.java:574) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.Choreographer.doFrame(Choreographer.java:544) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.os.Handler.handleCallback(Handler.java:733) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.os.Handler.dispatchMessage(Handler.java:95) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.os.Looper.loop(Looper.java:136) 07-06 20:51:50.251: E/AndroidRuntime(8151): at android.app.ActivityThread.main(ActivityThread.java:5001) 07-06 20:51:50.251: E/AndroidRuntime(8151): at java.lang.reflect.Method.invokeNative(Native Method) 07-06 20:51:50.251: E/AndroidRuntime(8151): at java.lang.reflect.Method.invoke(Method.java:515) 07-06 20:51:50.251: E/AndroidRuntime(8151): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785) 07-06 20:51:50.251: E/AndroidRuntime(8151): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601) 07-06 20:51:50.251: E/AndroidRuntime(8151): at dalvik.system.NativeStart.main(Native Method) 

您应该使用ViewPager.getAdapter()。getCount()getAdapter()方法返回为ViewPager提供页面的对象。

在OnCreate()中:

  ViewPager vp = (ViewPager) findViewById(R.id.viewPager); System.out.println(vp.getChildCount()); 

以下代码对我来说很好:

 public class ViewFlipperMainActivity extends Activity { private ViewFlipper viewFlipper; private float lastX; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.help_flipper); viewFlipper = (ViewFlipper) findViewById(R.id.view_flipper); System.out.println(viewFlipper.getChildCount()); } }