如何使用导航抽屉选择ViewPager

Question

I'm completely new to android app development and I'm currently working on a project for school.

From my understanding so far, you can use the navigation drawer to swap out UI fragments. I made a nav drawer that's working properly so far based on the tutorial given here:

https://developer.android.com/training/implementing-navigation/nav-drawer.html

I'm trying to have it switch views for each item that's selected. I made a view pager fragment activity and I want the program to replace the view with my view pager upon selecting the 4th item in the nav drawer (index 3). I added a switch statement in my fragment class to determine which layout to load.

Here's the activity for the nav drawer:

package com.mkge.mkg;

import android.content.res.Configuration;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.widget.DrawerLayout;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class MainActivity extends FragmentActivity {
    private DrawerLayout mDrawerLayout;
    private ListView mDrawerList;
    private ActionBarDrawerToggle mDrawerToggle;

    private CharSequence mTitle;
    private String[] mPageTitles;

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

        mTitle = getTitle();
        mPageTitles = getResources().getStringArray(R.array.nav_draw_array);
        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        mDrawerList = (ListView) findViewById(R.id.left_drawer);

        mDrawerList.setAdapter(new ArrayAdapter<String>(this, R.layout.drawer_list_item, mPageTitles));
        mDrawerList.setOnItemClickListener(new DrawerItemClickListener());

        getActionBar().setDisplayHomeAsUpEnabled(true);
        getActionBar().setHomeButtonEnabled(true);

        mDrawerToggle = new ActionBarDrawerToggle(
                this,
                mDrawerLayout,
                R.drawable.ic_drawer,
                R.string.drawer_open,
                R.string.drawer_close
                ) {
            public void onDrawerClosed(View view) {
                getActionBar().setTitle(mTitle);
                invalidateOptionsMenu();
            }

            public void onDrawerOpened(View drawerView) {
                getActionBar().setTitle(R.string.drawer_open);
                invalidateOptionsMenu();
            }
        };
        mDrawerLayout.setDrawerListener(mDrawerToggle);

        if (savedInstanceState == null) {
            selectItem(0);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.main, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (mDrawerToggle.onOptionsItemSelected(item)) return true;
        return super.onOptionsItemSelected(item);
    }

    private class DrawerItemClickListener implements ListView.OnItemClickListener {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            selectItem(position);
        }
    }

    private void selectItem(int position) {
        Fragment fragment = new PageFragment();
        Bundle args = new Bundle();
        args.putInt(PageFragment.ARG_PAGE_NUMBER, position);
        fragment.setArguments(args);

        FragmentManager fragmentManager = getSupportFragmentManager();
        fragmentManager.beginTransaction().replace(R.id.content_frame, fragment).commit();

        mDrawerList.setItemChecked(position, true);
        setTitle(mPageTitles[position]);
        mDrawerLayout.closeDrawer(mDrawerList);
    }

    public static class PageFragment extends Fragment {
        public static final String ARG_PAGE_NUMBER = "page_number";

        public PageFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            int i = getArguments().getInt(ARG_PAGE_NUMBER);
            View rootView;
            switch(i) {
            case 0:
                rootView = inflater.inflate(R.layout.page_home, container, false);
                break;
            case 1:
                rootView = inflater.inflate(R.layout.page_services, container, false);
                break;
            case 2:
                rootView = inflater.inflate(R.layout.page_packages, container, false);
                break;
            case 3:
            View view = new MeetViewPager().getViewPager();
            rootView = view;
            break;
            case 4:
                rootView = inflater.inflate(R.layout.page_about, container, false);
                break;
            case 5:
                rootView = inflater.inflate(R.layout.page_contact, container, false);
                break;
            case 6:
                rootView = inflater.inflate(R.layout.page_extras, container, false);
                break;
            default:
                rootView = null;
            }

            String page = getResources().getStringArray(R.array.nav_draw_array)[i];
            getActivity().setTitle(page);
            return rootView;
        }
    }

    @Override
    public void setTitle(CharSequence title) {
        mTitle = title;
        getActionBar().setTitle(mTitle);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        mDrawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        mDrawerToggle.onConfigurationChanged(newConfig);
    }
}

I made this fragment activity here to create the view pager. I tried taking the view pager object I made here and passing it to the switch statement to my nav drawer activity.

package com.mkge.mkg;

import java.util.ArrayList;
import java.util.List;

import android.annotation.SuppressLint;
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.View;
import android.view.ViewGroup;

@SuppressLint("ValidFragment")
    public class MeetViewPager extends FragmentActivity {
        public ViewPager mViewPager;
        public FragmentPagerAdapter mViewPagerAdapter;

        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.page_meet);
            List<Fragment> fragments = getFragments();
            mViewPager = (ViewPager) findViewById(R.id.pager);
            mViewPagerAdapter = new mPageAdapter(getSupportFragmentManager(), fragments);
            mViewPager.setAdapter(mViewPagerAdapter);
        }

        public View getViewPager() {
            return mViewPager;
        }

        private List<Fragment> getFragments() {
            List<Fragment> fList = new ArrayList<Fragment>();
            Fragment fragment = new mFragment();
            Bundle args = new Bundle();
            args.putInt("position", 0);
            fragment.setArguments(args);
            fList.add(fragment);

            fragment = new mFragment();
            args = new Bundle();
            args.putInt("position", 1);
            fragment.setArguments(args);
            fList.add(fragment);

            return fList;
        }

        private class mPageAdapter extends FragmentPagerAdapter {
            private List<Fragment> fragments;

            public mPageAdapter(FragmentManager f, List<Fragment> fragments) {
                super(f);
                this.fragments = fragments;
            }

            @Override
            public Fragment getItem(int position) {
                return this.fragments.get(position);
            }

            @Override
            public int getCount() {
                return this.fragments.size();
            }
        }

        @SuppressLint("ValidFragment")
        public static class mFragment extends Fragment {

            public mFragment() {
            }

            public static final mFragment newInstance(int i) {
                mFragment f = new mFragment();
                Bundle args = new Bundle(1);
                args.putInt("position", i);
                f.setArguments(args);
                return f;
            }

            public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
                View v;
                int i = getArguments().getInt("postion");
                switch(i) {
                case 0:
                    v = inflater.inflate(R.layout.page_meet_0, container, false);
                    break;
                case 1:
                    v = inflater.inflate(R.layout.page_meet_1, container, false);
                    break;
                default:
                    v = null;
                }
                return v;
            }
        }
    }

Any help would be appreciated thanks.

Answer 1

mViewPager.setCurrentItem(0); 

This should be all you need to make your ViewPager change to the first tab.

This would be called from inside your selectItem() method.