我正在开发一个简单的Android应用程序。我有一个测验会议。还有一个包含Categories，Question和Options的数据库。在我的activity_main上，我想动态显示问题和相应的选项。到目前为止，这些问题都是动态的（如果我按下tab 3，我会看到＃3的问题文本），但是，我不明白如何更改选项。我目前通过向线性布局添加按钮来放置虚拟值。请帮帮我！
public class QuizSessionActivity extends FragmentActivity implements ActionBar.TabListener {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections.
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
QuestionPagesAdapter mQuestionPagerAdapter;
QuizDB db;
//static Question curr;
/**
* The {@link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
String category;
static List<Question> questions;
static int pos;
/**
* Create the activity. Sets up an {@link android.app.ActionBar} with tabs, and then configures the
* {@link ViewPager} contained inside R.layout.activity_main.
*
* <p>A {@link QuestionPagesAdapter} will be instantiated to hold the different pages of
* fragments that are to be displayed. A
* {@link android.support.v4.view.ViewPager.SimpleOnPageChangeListener} will also be configured
* to receive callbacks when the user swipes between pages in the ViewPager.
*
* @param savedInstanceState
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent intent = getIntent();
category = intent.getStringExtra("cat");
// !!!!! Put real questions here
// Set up the action bar. The navigation mode is set to NAVIGATION_MODE_TABS, which will
// cause the ActionBar to render a set of tabs. Note that these tabs are *not* rendered
// by the ViewPager; additional logic is lower in this file to synchronize the ViewPager
// state with the tab state. (See mViewPager.setOnPageChangeListener() and onTabSelected().)
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.
mQuestionPagerAdapter = new QuestionPagesAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mQuestionPagerAdapter);
// 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 < mQuestionPagerAdapter.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(mQuestionPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu_quiz, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_finish:
// TODO: Handle finish here
}
return super.onOptionsItemSelected(item);
}
/**
* Update {@link ViewPager} after a tab has been selected in the ActionBar.
*
* @param tab Tab that was selected.
* @param fragmentTransaction A {@link android.app.FragmentTransaction} for queuing fragment operations to
* execute once this method returns. This FragmentTransaction does
* not support being added to the back stack.
*/
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
// When the given tab is selected, tell the ViewPager to switch to the corresponding page.
pos = tab.getPosition();
Fragment fragment = new QuestionSectionFragment();
mViewPager.setCurrentItem(tab.getPosition());
}
/**
* Unused. Required for {@link android.app.ActionBar.TabListener}.
*/
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
/**
* Unused. Required for {@link android.app.ActionBar.TabListener}.
*/
@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages. This provides the data for the {@link ViewPager}.
*/
public class QuestionPagesAdapter extends FragmentStatePagerAdapter {
public QuestionPagesAdapter(FragmentManager fm) {
super(fm);
}
/**
* Get fragment corresponding to a specific position. This will be used to populate the
* contents of the {@link ViewPager}.
*
* @param position Position to fetch fragment for.
* @return Fragment for specified position.
*/
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a QuestionSectionFragment (defined as a static inner class
// below) with the page number as its lone argument.
Fragment fragment = new QuestionSectionFragment();
Bundle args = new Bundle();
// Put real questions here
db = new QuizDB(getApplicationContext());
questions = db.getCategoryQuestions(category);
args.putString(QuestionSectionFragment.ARG_QUESTION_NUMBER, ""+(position + 1));
args.putString(QuestionSectionFragment.ARG_QUESTION_TEXT, questions.get(position).getBodyText());
fragment.setArguments(args);
//curr = questions.get(pos);
return fragment;
}
/**
* Get number of pages the {@link ViewPager} should render.
*
* @return Number of fragments to be rendered as pages.
*/
@Override
public int getCount() {
// Show 10 total pages.
return 10;
}
/**
* Get title for each of the pages. This will be displayed on each of the tabs.
*
* @param position Page to fetch title for.
* @return Title for specified page.
*/
@Override
public CharSequence getPageTitle(int position) {
return new Integer(position + 1).toString();
}
}
/**
* A dummy fragment representing a section of the app, but that simply displays dummy text.
* This would be replaced with your application's content.
*/
public static class QuestionSectionFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
public static final String ARG_QUESTION_NUMBER = "question_number";
public static final String ARG_QUESTION_TEXT = "question_text";
public QuestionSectionFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
TextView questionTextView = (TextView) rootView.findViewById(R.id.question_text);
Bundle args = getArguments();
questionTextView.setText(args.getString(ARG_QUESTION_TEXT));
LinearLayout answerBox = (LinearLayout) rootView.findViewById(R.id.question_box);
for(int i = 1; i <= 4; i++) {
Button option = new Button(getActivity());
// real answer options here
option.setText(questions.get(pos).getOptions().get(i - 1).getOptionText());
option.setContentDescription(String.format("q%s_o%s", args.getString(ARG_QUESTION_NUMBER), i));
answerBox.addView(option);
}
return rootView;
}
/*
public void onClick(View v) {
View rootView = v;
TextView questionTextView = (TextView) rootView.findViewById(R.id.question_text);
Bundle args = getArguments();
questionTextView.setText(args.getString(ARG_QUESTION_TEXT));
LinearLayout answerBox = (LinearLayout) rootView.findViewById(R.id.question_box);
for(int i = 1; i <= 4; i++) {
Button option = new Button(getActivity());
// real answer options here
option.setText(questions.get(pos).getOptions().get(i - 1).getOptionText());
option.setContentDescription(String.format("q%s_o%s", args.getString(ARG_QUESTION_NUMBER), i));
answerBox.addView(option);
}
}*/
}