Android ViewPager活动

时间:2013-09-10 01:33:15

标签: android eclipse android-viewpager android-pageradapter

经过对该主题的广泛研究后,我陷入了僵局。我正在尝试从Android的“Using ViewPager for Screen Slides”教程中实现ViewPager,以便在每个页面上显示不同的文本,就像您正在浏览书籍中的页面一样。它的设置方式是,它们有两个XML文件(一个在Fragment Activity类中实现ViewPager元素,一个在Fragment类中有一个textview),在每个页面上显示Lorem Ipsum。我正在尝试找到一种方法来更改Fragment类中的textview,这样当我转到第2,3,4页等时,每页上都会有不同的文本。

ScreenSlideActivity类中,我尝试在onPageScrollStateChanged(int position)内部事件处理程序中使用切换,将某些文本视图设置为可见/不可见。我还尝试在onCreateView(LayoutInflater inflater,ViewGroup容器,Bundle savedInstanceState)方法的ScreenSlidePageFragment类中使用一个开关。这是正确的方法还是我离开了?我肯定会忽视一些事情,有些人可以指出我正确的方向吗?

这是使用Eclipse定位API 14到17的构建。下面是两个类中的一些代码,以及带有textview的XML文件:

//片段活动类//

public class ScreenSlideActivity extends FragmentActivity {
/**
 * The number of pages (wizard steps) to show in this demo.
 */
private static final int NUM_PAGES = 5;

/**
 * The pager widget, which handles animation and allows swiping horizontally to access previous
 * and next wizard steps.
 */
private ViewPager mPager;

/**
 * The pager adapter, which provides the pages to the view pager widget.
 */
private PagerAdapter mPagerAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_screen_slide);
    getActionBar().setDisplayHomeAsUpEnabled(true);

 // Instantiate a ViewPager and a PagerAdapter.
    mPager = (ViewPager) findViewById(R.id.pager);
    mPagerAdapter = new ScreenSlidePagerAdapter(getFragmentManager());
    mPager.setAdapter(mPagerAdapter);
    mPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
        @Override
        public void onPageSelected(int position) {
            // When changing pages, reset the action bar actions since they are dependent
            // on which page is currently active. An alternative approach is to have each
            // fragment expose actions itself (rather than the activity exposing actions),
            // but for simplicity, the activity provides the actions in this sample.

            invalidateOptionsMenu();
        }
    });
}

private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
    public ScreenSlidePagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {

        return ScreenSlidePageFragment.create(position);
    }

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

//片段类//

public class ScreenSlidePageFragment extends Fragment {
/**
 * The argument key for the page number this fragment represents.
 */
public static final String ARG_PAGE = "page";

/**
 * The fragment's page number, which is set to the argument value for {@link #ARG_PAGE}.
 */
private int mPageNumber;

/**
 * Factory method for this fragment class. Constructs a new fragment for the given page number.
 */
public static ScreenSlidePageFragment create(int pageNumber) {
    ScreenSlidePageFragment fragment = new ScreenSlidePageFragment();
    Bundle args = new Bundle();
    args.putInt(ARG_PAGE, pageNumber);
    fragment.setArguments(args);
    return fragment;
}

public ScreenSlidePageFragment() {
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mPageNumber = getArguments().getInt(ARG_PAGE);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    ViewGroup rootView = (ViewGroup) inflater
            .inflate(R.layout.fragment_screen_slide_page, container, false);

    // Set the title view to show the page number.
    ((TextView) rootView.findViewById(android.R.id.text1)).setText(
            getString(R.string.title_template_step, mPageNumber + 1));

    return rootView;
}

/**
 * Returns the page number represented by this fragment object.
 */
public int getPageNumber() {
    return mPageNumber;
}

}

// XML layout //

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/content"
android:layout_width="match_parent"
android:layout_height="match_parent">

<!-- Dummy content. -->
<LinearLayout android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="16dp">

    <TextView android:id="@android:id/text1"
        style="?android:textAppearanceLarge"
        android:textStyle="bold"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp" />

    <TextView
        android:id="@+id/lorem_ipsum1"
        style="?android:textAppearanceMedium"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:lineSpacingMultiplier="1.2"
        android:text="@string/lorem_ipsum" />

</LinearLayout>

1 个答案:

答案 0 :(得分:0)

问题已解决,我必须在ScreenSlidePageFragment内创建一个switch语句,关闭/打开可见性(VISIBILEGONE),具体取决于mPageNumber变量(即页码确定为该页面设置的字符串值)。这是一项黑客工作,效率低下,还是很好?最重要的是,它的工作原理。所有字符串都保存在strings.xml中。同样,不确定这是否适用于较大的字符串。

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    ViewGroup rootView = (ViewGroup) inflater
            .inflate(R.layout.fragment_screen_slide_page, container, false);

    // Set the title view to show the page number.
    ((TextView) rootView.findViewById(android.R.id.text1)).setText(
            getString(R.string.title_template_step, mPageNumber + 1));

    switch(mPageNumber){
        case 0:
            rootView.findViewById(R.id.lorem_ipsum1).setVisibility(View.VISIBLE);
            rootView.findViewById(R.id.lorem_ipsum2).setVisibility(View.GONE);
            rootView.findViewById(R.id.lorem_ipsum3).setVisibility(View.GONE);
            break;
        case 1:
            rootView.findViewById(R.id.lorem_ipsum1).setVisibility(View.GONE);
            rootView.findViewById(R.id.lorem_ipsum2).setVisibility(View.VISIBLE);
            rootView.findViewById(R.id.lorem_ipsum3).setVisibility(View.GONE);
            break;
        case 2:
          rootView.findViewById(R.id.lorem_ipsum1).setVisibility(View.GONE);
          rootView.findViewById(R.id.lorem_ipsum2).setVisibility(View.GONE);
          rootView.findViewById(R.id.lorem_ipsum3).setVisibility(View.VISIBLE);
          break;
        }

    return rootView;
}