问题
I'm having a bit of trouble having the ViewPager displaying and running properly with a single fragment class.
So a bit of background. The Activity itself is supposed to allow users to answer questions in a survey. Each question consists of a question title, an input box, and a submit button. I've made a layout and a corresponding fragment (QuestionFragment) class to hold all of this.
My idea is to have the ViewPager hold a bunch of QuestionFragment's and the user will be able to swipe to the questions they would like to answer or edit. Basically each page will be using a QuestionFragment, but each will contain a unique question.
However my implementation doesn't look like its working out. The first page in the activity will have the UI set up (page 1) but the rest of the pages will have the default layout xml applied.
Note: at the moment I'm trying to set up the UI with the index number. You can ignore the Question[] array and any reference to it as the UI doesnt use it at this time. However I do try to set the typeface, which only works on the first page. You can take a look at the screenshots at the bottom, "How many moons does Saturn have" is the default xml in the layout. I've also noticed that the textview displays question 9, instead of 1.
Here is the fragment
public class SurveyTakerFragment extends Fragment {
private Question question;
private int index;
private TextView tv_question_title;
private EditText et_sms_response;
private Button btn_submit_response;
private SharedPreferences sharedPrefs;
private Typeface typeface;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_question, container, false);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setup();
}
void setup(){
Activity activity = getActivity();
tv_question_title = (TextView) activity.findViewById(R.id.tv_question_title);
et_sms_response = (EditText) activity.findViewById(R.id.et_sms_response);
btn_submit_response = (Button) activity.findViewById(R.id.btn_submit_response);
tv_question_title.setTypeface(typeface);
tv_question_title.setText("Question: " + index);
//TODO: Set question title.
//TODO: Pre-fill previous answer if any.
btn_submit_response.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
String response = et_sms_response.getText().toString();
//TODO: Submit response.
}
});
}
public void setQuestion(Question question, int index){
this.question = question;
this.index = index;
}
public void setSharedPrefs(SharedPreferences sharedPrefs){
this.sharedPrefs = sharedPrefs;
}
public void setTypeface(Typeface typeface){
this.typeface = typeface;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
}
}
Here is the adapter:
public class SurveyTakerAdapter extends FragmentPagerAdapter{
private Question[] questions;
private SharedPreferences sharedPrefs;
private Typeface typeface;
public SurveyTakerAdapter(FragmentManager fm, Question[] questions,
SharedPreferences sharedPrefs, Typeface typeface) {
super(fm);
this.questions = questions;
this.sharedPrefs = sharedPrefs;
this.typeface = typeface;
}
@Override
public Fragment getItem(int index) {
SurveyTakerFragment surveyTakerFragment = new SurveyTakerFragment();
surveyTakerFragment.setQuestion(questions[index], index);
surveyTakerFragment.setSharedPrefs(sharedPrefs);
surveyTakerFragment.setTypeface(typeface);
return surveyTakerFragment;
}
@Override
public int getCount() {
return questions.length;
}
@Override
public CharSequence getPageTitle(int position) {
return "Question: " + (position + 1);
}
}
Pager Activity
public class SurveyTaker extends FragmentActivity{
private final String APP_DATA = "appData";
private SurveyTakerAdapter surveyTakerAdapter;
private ViewPager viewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_survey);
Question[] questions = new Question[10];
FragmentManager fragmentManager = getSupportFragmentManager();
SharedPreferences sharedPrefs = getSharedPreferences(APP_DATA, MODE_PRIVATE);
Typeface robot = Typeface.createFromAsset(getAssets(), "Roboto-Thin.ttf");
surveyTakerAdapter = new SurveyTakerAdapter(fragmentManager, questions, sharedPrefs, robot);
viewPager = (ViewPager) findViewById(R.id.vp_survey_taker);
viewPager.setOffscreenPageLimit(10);
viewPager.setAdapter(surveyTakerAdapter);
viewPager.setOnPageChangeListener(new OnPageChangeListener() {
@Override
public void onPageSelected(int index) {
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
// TODO Auto-generated method stub
}
@Override
public void onPageScrollStateChanged(int arg0) {
// TODO Auto-generated method stub
}
});
}
}
I'm assuming this is the case because I'm using a single fragment to populate all the pages in the viewpager, but I don't know how else to go about this. Is my design bad? Or is there something im missing?
Any help would be greatly appreciated! Thanks!
回答1:
It looks like the R.id.tv_question_title, R.id.tv_question_title and R.id.tv_question_title views are part of your R.layout.fragment_question layout. You should be referencing those views through your SurveyTakerFragment instance using getView(), not through the Activity via getActivity(). You are also duplicating effort in onActivityCreated() and setup().
Replace your onActivityCreated() and setup() implementations with this:
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setup();
}
void setup(){
View view = getView();
tv_question_title = (TextView) view.findViewById(R.id.tv_question_title);
et_sms_response = (EditText) view.findViewById(R.id.et_sms_response);
btn_submit_response = (Button) view.findViewById(R.id.btn_submit_response);
tv_question_title.setTypeface(typeface);
tv_question_title.setText("Question: " + index);
//TODO: Set question title.
//TODO: Pre-fill previous answer if any.
btn_submit_response.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
String response = et_sms_response.getText().toString();
//TODO: Submit response.
}
});
}
来源：https://stackoverflow.com/questions/22263672/android-viewpager-using-a-single-fragment-on-multiple-pages