使用ViewPager和Fragment實現滑動導航

ViewPage是android-support-v4.jar包提供的用于頁面滑動的庫,android-support-v4.jar是google推薦使用的一個類庫,在項目中使用之前,你必須其添加到項目中(項目點右鍵Build path->configure build path,然后找到jar進行添加)

1.在xml布局文件中添加android.support.v4.view.ViewPager容器及顯示導航所用標簽android.support.v4.view.PagerTitleStrip,如我添加的xml內容如下

<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <!--
    This title strip will display the currently visible page title, as well as the page
    titles for adjacent pages.
    -->

    <android.support.v4.view.PagerTitleStrip
        android:id="@+id/pager_title_strip"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="top"
        android:background="#33b5e5"
        android:paddingBottom="4dp"
        android:paddingTop="4dp"
        android:textColor="#fff" />

</android.support.v4.view.ViewPager>

import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;

3.聲明變量

SectionsPagerAdapter mSectionsPagerAdapter;
ViewPager mViewPager;

mSectionsPagerAdapter = new SectionsPagerAdapter(
                getSupportFragmentManager());

// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);

public class SectionsPagerAdapter extends FragmentPagerAdapter {

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            // getItem is called to instantiate the fragment for the given page.
            // Return a DummySectionFragment (defined as a static inner class
            // below) with the page number as its lone argument.
            Fragment fragment = new HjFragment();
            Bundle args = new Bundle();
            args.putInt("no", position + 1);
            fragment.setArguments(args);

            return fragment;
        }

        @Override
        public int getCount() {
            // Show 3 total pages.
            return 3;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            switch (position) {
            case 0:
                return "標簽1";
            case 1:
                return "標簽2";
            case 2:
                return "標簽3";
            }
            return null;
        }
    }

可以看到在getItem中返回了一個Fragment,這個就是當滑動到不同標簽時顯示在ViewPager中的內容,Fragment相當于一個Activity,在可以其中的onCreateView函數中構造需要顯示的內容并返回

比如,以下代碼將顯示一個文本信息

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    TextView textView = new TextView(getActivity());
    textView.setGravity(Gravity.CENTER);
    textView.setText("你選擇了標簽:"+Integer.toString(getArguments().getInt(
            "no")));
    return textView;

}