当我通过任何片段切换时，我的应用程序停止（使用Page Viewer）。基本上，如果没有应用程序停止，我根本无法刷到任何片段。我得到的错误是“不幸的是，TestareNou已经停止了”。
这是我的MainActivity Class的代码：
package com.example.testarenou;
import java.util.Locale;
import android.app.ActionBar;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class MainActivity extends FragmentActivity implements ActionBar.TabListener {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
* will keep every loaded fragment in memory. If this becomes too memory
* intensive, it may be best to switch to a
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Create the adapter that will return a fragment for each of the three
// primary sections of the app.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
// When swiping between different sections, select the corresponding
// tab. We can also use ActionBar.Tab#select() to do this if we have
// a reference to the Tab.
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by
// the adapter. Also specify this Activity object, which implements
// the TabListener interface, as the callback (listener) for when
// this tab is selected.
actionBar.addTab(
actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {Fragment f = null;
switch(position){
case 0:
{
f = new DummySectionFragment();//YourFragment
// set arguments here, if required
Bundle args = new Bundle();
f.setArguments(args);
break;
}
case 1:
{
f = new Fragment2();//YourFragment
// set arguments here, if required
Bundle args = new Bundle();
f.setArguments(args);
break;
}
default:
throw new IllegalArgumentException("not this many fragments: " + position);
}
return f;
}
@Override
public int getCount() {
// Show 3 total pages.
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.title_section1).toUpperCase(l);
case 1:
return getString(R.string.title_section2).toUpperCase(l);
case 2:
return getString(R.string.title_section3).toUpperCase(l);
}
return null;
}
}
/**
* A dummy fragment representing a section of the app, but that simply
* displays dummy text.
*/
public static class DummySectionFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
public static final String ARG_SECTION_NUMBER = "section_number";
public DummySectionFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main_dummy, container, false);
TextView dummyTextView = (TextView) rootView.findViewById(R.id.section_label);
dummyTextView.setText(Integer.toString(getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
}
} public static class Fragment2 extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
public static final String ARG_SECTION_NUMBER = "section_number";
public Fragment2() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment2, container, false);
TextView dummyTextView = (TextView) rootView.findViewById(R.id.section_label);
dummyTextView.setText(Integer.toString(getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
}
}
}
这是Log Cat :(截图：http://s8.postimg.org/welool4v9/Log_Cat.jpg）
08-27 07:00:34.246: W/Trace(1791): Unexpected value from nativeGetEnabledTags: 0
08-27 07:00:34.246: I/Choreographer(1791): Skipped 40 frames! The application may be doing too much work on its main thread.
08-27 07:00:34.297: D/AndroidRuntime(1791): Shutting down VM
08-27 07:00:34.297: W/dalvikvm(1791): threadid=1: thread exiting with uncaught exception (group=0xb4cd0908)
08-27 07:00:34.327: E/AndroidRuntime(1791): FATAL EXCEPTION: main
08-27 07:00:34.327: E/AndroidRuntime(1791): java.lang.IllegalArgumentException: not this many fragments: 2
08-27 07:00:34.327: E/AndroidRuntime(1791): at com.example.testarenou.MainActivity$SectionsPagerAdapter.getItem(MainActivity.java:129)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.support.v4.app.FragmentPagerAdapter.instantiateItem(FragmentPagerAdapter.java:97)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:832)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.support.v4.view.ViewPager.populate(ViewPager.java:1048)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.support.v4.view.ViewPager.populate(ViewPager.java:914)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.support.v4.view.ViewPager$3.run(ViewPager.java:244)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.view.Choreographer.doCallbacks(Choreographer.java:562)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.view.Choreographer.doFrame(Choreographer.java:531)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.os.Handler.handleCallback(Handler.java:725)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.os.Handler.dispatchMessage(Handler.java:92)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.os.Looper.loop(Looper.java:137)
08-27 07:00:34.327: E/AndroidRuntime(1791): at android.app.ActivityThread.main(ActivityThread.java:5039)
08-27 07:00:34.327: E/AndroidRuntime(1791): at java.lang.reflect.Method.invokeNative(Native Method)
08-27 07:00:34.327: E/AndroidRuntime(1791): at java.lang.reflect.Method.invoke(Method.java:511)
08-27 07:00:34.327: E/AndroidRuntime(1791): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
08-27 07:00:34.327: E/AndroidRuntime(1791): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
08-27 07:00:34.327: E/AndroidRuntime(1791): at dalvik.system.NativeStart.main(Native Method)
如果需要提供任何其他类型的信息，请告诉我。
答案 0 :(得分：1)
在getCount()函数中，您告诉适配器您有3页
@Override
public int getCount() {
// Show 3 total pages.
return 3;
}
但是当适配器尝试获取视图时，您只提供了两个页面，即0和1
@Override
public Fragment getItem(int position) {Fragment f = null;
switch(position){
case 0:
{
f = new DummySectionFragment();//YourFragment
// set arguments here, if required
Bundle args = new Bundle();
f.setArguments(args);
break;
}
case 1:
{
f = new Fragment2();//YourFragment
// set arguments here, if required
Bundle args = new Bundle();
f.setArguments(args);
break;
}
default:
throw new IllegalArgumentException("not this many fragments: " + position);
}
return f;
}
这个例外甚至是你自己创造的！因此，要么将getCount()更改为2，要么将case 2:添加到getItem()。