如何在Android中使用ViewPager进行无限制的寻呼机

Question

当我滑动月份视图时，我想在我的日历中显示无限制的viewpager。我怎样才能做到这一点？我想我需要3个片段才能做到这一点。但是，当我向左或向右滑动时，我不知道如何更新月份（片段）。我在下面附上了我的代码。我给出了我不知道编码的问号。 这是我的项目：https://github.com/lolyoshi/CalendarWidget

感谢任何帮助。

InfinitedPagerAdapter.java

public class InfinitePagerAdapter extends FragmentPagerAdapter{

    CalendarView[] fragList;  
    int fragNumber = 3;

    public InfinitePagerAdapter(FragmentManager fm, CalendarView[] fragList) {
        super(fm);
        this.fragList = fragList;
    }

    @Override
    public int getItemPosition(Object object) {
        // TODO Auto-generated method stub
        return POSITION_NONE;
    }

    @Override
    public Fragment getItem(int position) {
        return fragList[position];      
    }

    @Override
    public int getCount() {
        return fragNumber;
    }

    public void setCalendar(????) {
          //Need to update 3 fragments
           ??????????????????????
    }

    @Override
    public boolean isViewFromObject(View arg0, Object arg1) {
        // TODO Auto-generated method stub
        return false;
    }
}

CalendarWidget.java

public class CalendarWidget extends FragmentActivity {
    ViewPager monthPage;
    private static final int PAGE_MIDDLE = 1;
    private int mSelectedPageIndex = 1;
    public Calendar curMonth;
    InfinitePagerAdapter monthPageAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.calendar_layout);

        CalendarView[] fragList = new CalendarView[3];
        curMonth = Calendar.getInstance();
        Calendar prevMonth, nextMonth;
        prevMonth = (Calendar) curMonth.clone();
        nextMonth = (Calendar) curMonth.clone();
        prevMonth.set(Calendar.MONTH, prevMonth.get(Calendar.MONTH) - 1);
        nextMonth.set(Calendar.MONTH, nextMonth.get(Calendar.MONTH) + 1);
        fragList[0] = CalendarView.newInstance(prevMonth);
        fragList[1] = CalendarView.newInstance(curMonth);
        fragList[2] = CalendarView.newInstance(nextMonth);

        monthPage = (ViewPager)findViewById(R.id.pager);
        monthPageAdapter = new InfinitePagerAdapter(getSupportFragmentManager(), fragList);
        monthPage.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

            @Override
            public void onPageScrollStateChanged(int arg0) {
                // TODO Auto-generated method stub
                 if (mSelectedPageIndex < PAGE_MIDDLE) {
                     curMonth.add(Calendar.MONTH, -1);
                    } else if (mSelectedPageIndex > PAGE_MIDDLE) {
                        curMonth.add(Calendar.MONTH, 1);    
                    }
                                        //Need to update 3 fragments
                    monthPageAdapter.setCalendar(????);
                        monthPage.setCurrentItem(1, false);
            }

            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
                // TODO Auto-generated method stub

            }

            @Override
            public void onPageSelected(int arg0) {
                // TODO Auto-generated method stub
                mSelectedPageIndex = arg0;
            }});
        monthPage.setAdapter(monthPageAdapter);
        monthPage.setCurrentItem(1, false);
    }    
}

CalendarView.java

public class CalendarView extends Fragment{
    protected static Calendar calendar;
    protected final Calendar itemMonth;
    private CalendarAdapter calendarAdapter;
    private LinearLayout calendarLayout;
    public ArrayList<String> items;
    ArrayList<String> event;
    ArrayList<String> desc;
    public Handler handler;
    private int mMonth, mYear;

    private static final int PAGE_LEFT = 0;
    private static final int PAGE_MIDDLE = 1;
    private static final int PAGE_RIGHT = 2;

    static CalendarView newInstance(?????) {
        //What can I put in this function?
        return f;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        calendarLayout = (LinearLayout)inflater.inflate(R.layout.calendar_layout, container, false);
        final GridView calendarDayGrid = (GridView)calendarLayout.findViewById(R.id.calendar_days_grid);
        calendarDayGrid.setAdapter(new ArrayAdapter<String>(getActivity(), R.layout.day_cell, getResources().getStringArray(R.array.days_array)));
        final GridView calendarGrid = (GridView)calendarLayout.findViewById(R.id.calendar_grid);
        calendarGrid.setOnTouchListener(new OnTouchListener(){
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if(event.getAction() == MotionEvent.ACTION_MOVE){
                    return true;
                }
                return false;
            }

        });
        calendarGrid.setOnItemClickListener(new DayItemClickListener());
        DisplayMetrics displaymetrics = new DisplayMetrics();
        getActivity().getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
        int height = displaymetrics.heightPixels;
        int width = displaymetrics.widthPixels;
        float gridHeight = height*3/4 - 3*(convertDpToPixels(50, getActivity())); //fix the height of table of days in week = 25dp
        calendarAdapter = new CalendarAdapter(getActivity(), calendar, gridHeight);
        updateCurrentMonth();         
        calendarGrid.setAdapter(calendarAdapter);
        return calendarLayout;
    }

    public CalendarView() {
        calendar = Calendar.getInstance();
        itemMonth = (Calendar) calendar.clone();
    }


    protected void updateCurrentMonth() {
        calendarAdapter.refreshDays();
        //handler.post(calendarUpdater);
        TextView month = (TextView)calendarLayout.findViewById(R.id.month_title);        
        month.setTextColor(Color.BLACK);
        int monthID = calendar.get(Calendar.MONTH);
        int[] monthIds = {R.string.january,R.string.february,R.string.march,R.string.april,R.string.may,R.string.june,
                R.string.july,R.string.august,R.string.september,R.string.october,R.string.november,R.string.december};
        month.setText(monthIds[monthID]);
        String tmp = (String) month.getText();
        month.setText(tmp + " " + calendar.get(Calendar.YEAR));
    }

    protected final void onNextMonth() {
        if (calendar.get(Calendar.MONTH) == Calendar.DECEMBER) {
            calendar.set((calendar.get(Calendar.YEAR) + 1), Calendar.JANUARY, 1);
        } else {
            calendar.set(Calendar.MONTH, calendar.get(Calendar.MONTH) + 1);
        }
        updateCurrentMonth(calendar);
    }

    protected final void onPreviousMonth() {
        if (calendar.get(Calendar.MONTH) == Calendar.JANUARY) {
            calendar.set((calendar.get(Calendar.YEAR) - 1), Calendar.DECEMBER, 1);
        } else {
            calendar.set(Calendar.MONTH, calendar.get(Calendar.MONTH)-1);
        }
        updateCurrentMonth(calendar);
    }

    public static float convertDpToPixels(float dp,Context context){
        Resources resources = context.getResources();
        DisplayMetrics metrics = resources.getDisplayMetrics();
        float px = dp * (metrics.densityDpi/160f);
        return px;
    }

    public static float convertPixelsToDp(float px,Context context){
        Resources resources = context.getResources();
        DisplayMetrics metrics = resources.getDisplayMetrics();
        float dp = px / (metrics.densityDpi / 160f);
        return dp;   
    }

    private final class DayItemClickListener implements OnItemClickListener {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            final TextView dayView = (TextView)view.findViewById(R.id.date_in_cell);
            final CharSequence text = dayView.getText();
            if (text != null && !"".equals(text)) {
                calendarAdapter.setSelected(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH), Integer.valueOf(String.valueOf(text)));
            }
        }       
    }
}

Answer 1

您滑动时月份未更新的原因是您已声明protected static Calendar calendar;静态。删除静态后，所有三个页面都显示不同的月份。

保持您的日历视图与github一样，除了此更改：

static CalendarView newInstance(Calendar a) {
    CalendarView f = new CalendarView(a);
    return f;
}

public CalendarView(Calendar cal) {
    calendar = cal;
}

您的适配器将如下所示：

public class InfinitePagerAdapter extends FragmentPagerAdapter{

    CalendarView[] fragList;  

    public InfinitePagerAdapter(FragmentManager fm, CalendarView[] fragList) {
        super(fm);
        this.fragList = fragList;
    }

    @Override
    public Fragment getItem(int position) {
        return fragList[position];
    }

    @Override
    public int getCount() {
        return fragList.length;
    }
}

最后在您的日历小部件中修改如下：

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_calendar_widget);

        final CalendarView[] fragList = new CalendarView[3];
        curMonth = Calendar.getInstance();
        Calendar prevMonth, nextMonth;
        prevMonth = (Calendar) curMonth.clone();
        nextMonth = (Calendar) curMonth.clone();
        prevMonth.set(Calendar.MONTH, prevMonth.get(Calendar.MONTH) - 1);
        nextMonth.set(Calendar.MONTH, nextMonth.get(Calendar.MONTH) + 1);
        fragList[0] = CalendarView.newInstance(prevMonth);
        fragList[1] = CalendarView.newInstance(curMonth);
        fragList[2] = CalendarView.newInstance(nextMonth);

        monthPage = (ViewPager) findViewById(R.id.pager);
        monthPageAdapter = new InfinitePagerAdapter(getSupportFragmentManager(), fragList);
        monthPage.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

            @Override
            public void onPageScrollStateChanged(int arg0) {
                // TODO Auto-generated method stub
                if (arg0 == ViewPager.SCROLL_STATE_IDLE) {
                    if (mSelectedPageIndex < PAGE_MIDDLE) {
                        fragList[0].onPreviousMonth();
                        fragList[1].onPreviousMonth();
                        fragList[2].onPreviousMonth();
                    } else if (mSelectedPageIndex > PAGE_MIDDLE) {
                        fragList[0].onNextMonth();
                        fragList[1].onNextMonth();
                        fragList[2].onNextMonth();
                    }
                    monthPage.setCurrentItem(1, false);
                }
            }

            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
                // TODO Auto-generated method stub

            }

            @Override
            public void onPageSelected(int arg0) {
                // TODO Auto-generated method stub
                mSelectedPageIndex = arg0;
            }
        });
        monthPage.setAdapter(monthPageAdapter);
        monthPage.setCurrentItem(1, false);
    }

这就是你需要做的一切。一切都应该按照需要运作。

注意：尽管一切正常，但克隆和传递日历对象可能不是最好的选择。 Calendar个对象很贵。如果可能的话，你应该传递Time。从here

中获取一些动力