当XML文件包含imageviews时，有些滞后（断断续续）的ViewPager

Question

我有一个ViewPager，每个页面都有一个新的片段。我制作了一个片段来测试我的ViewPager，这个片段有一个如下所示的布局：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:orientation="vertical">
<TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="5dp"
        android:textAppearance="@android:style/TextAppearance.Large"
        android:text="@string/textView_ride_height_overview_heading"
        android:id="@+id/textView_ride_height_overview_heading"/>
<View
        android:layout_width="fill_parent"
        android:layout_height="2dp"
        android:layout_marginTop="2dp"
        android:background="#FFFF3BB2"
        android:id="@+id/view_ride_height_heading"/>
<ScrollView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:scrollbars="none">
    <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">
        <ImageView
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="10dp"
                android:layout_marginLeft="2dp"
                android:layout_marginRight="2dp"
                android:scaleType="fitXY"
                android:adjustViewBounds="true"
                android:background="@drawable/image_border"
                android:src="@drawable/ride_height_overview"
                android:contentDescription="@string/imageView_ride_height_overview_content_description"
                android:id="@+id/imageView_ride_height_overview"/>
        <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@id/imageView_ride_height_overview"
                android:layout_marginTop="10dp"
                android:layout_marginLeft="2dp"
                android:layout_marginRight="2dp"
                android:textAppearance="@android:style/TextAppearance.Medium"
                android:text="@string/textView_ride_height_overview_summary"/>
    </RelativeLayout>
</ScrollView>
</LinearLayout>

我使用了三个相同的片段来测试滑动功能。滑动不是太糟糕但与不包含任何图像视图的碎片相比仍然相对滞后。所以我怀疑我刷卡时所做的每一个动作都需要更长时间，因为图像需要在屏幕上重新绘制，这可能是罪魁祸首吗？

这是我的主屏幕处理程序，它包含您可以导航到的可能项目的列表视图。

public class MainScreenHandler extends Activity {

private ArrayList<SubScreenFragments> subScreenFragmentList = new ArrayList<SubScreenFragments>();

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main_screen_handler_layout);

    subScreenFragmentList.add(new SubScreenFragments("Ride height", new FragmentRideHeightOverview(), new FragmentRideHeightOverview(),
            new FragmentRideHeightOverview(), null));
    subScreenFragmentList.add(new SubScreenFragments("Toe", new FragmentRideHeightOverview(), new FragmentRideHeightOverview(),
            new FragmentRideHeightOverview(), null));

    String[] listViewNameArray = new String[subScreenFragmentList.size()];
    for (int i = 0; i < listViewNameArray.length; i++) {
        listViewNameArray[i] = subScreenFragmentList.get(i).getListViewName();
    }
    ListView listview = (ListView) findViewById(R.id.listview);
    listview.setClickable(true);
    ArrayAdapter<String> listAdapter = new ArrayAdapter<String>(this, R.layout.listview_row_layout, listViewNameArray);
    listview.setAdapter(listAdapter);
    listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
            Intent myIntent = new Intent(getBaseContext(), SubScreenHandler.class);
            Bundle myBundle = new Bundle();
            myBundle.putSerializable("fragmentList", subScreenFragmentList.get(i).getFragments());
            myIntent.putExtras(myBundle);
            startActivity(myIntent);
        }
    });
}
}

class SubScreenFragments {
    String listViewName;
    Fragment fragmentTab1, fragmentTab2, fragmentTab3, fragmentTab4;
public SubScreenFragments(String listViewName, Fragment fragmentTab1, Fragment fragmentTab2, Fragment fragmentTab3, Fragment fragmentTab4) {
    this.listViewName = listViewName;
    this.fragmentTab1 = fragmentTab1;
    this.fragmentTab2 = fragmentTab2;
    this.fragmentTab3 = fragmentTab3;
    this.fragmentTab4 = fragmentTab4;
}

public String getListViewName() {
    return listViewName;
}

public ArrayList<Fragment> getFragments() {
    ArrayList<Fragment> fragmentList = new ArrayList<Fragment>();
    if (fragmentTab1 != null)
        fragmentList.add(fragmentTab1);
    if (fragmentTab2 != null)
        fragmentList.add(fragmentTab2);
    if (fragmentTab3 != null)
        fragmentList.add(fragmentTab3);
    if (fragmentTab4 != null)
        fragmentList.add(fragmentTab4);
    return fragmentList;
 }
}

我的子屏幕处理程序，它处理viewpager的片段填充。

public class SubScreenHandler extends FragmentActivity{
@SuppressWarnings("unchecked")
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.sub_screen_handler_layout);
    ArrayList<Fragment> fragmentList=new ArrayList<Fragment>();
    fragmentList.addAll((ArrayList<Fragment>) getIntent().getSerializableExtra("fragmentList"));
    for (Object item : fragmentList) {
        if (!(item instanceof Fragment)) {
            throw new ClassCastException("List contained non-Fragment objects: " + item.getClass().getCanonicalName());
        }
    }
    ViewPager viewPager = (ViewPager) findViewById(R.id.viewPager);
    viewPager.setAdapter(new myPagerAdapter(getFragmentManager(), fragmentList));
    CirclePageIndicator circlePageIndicator = (CirclePageIndicator) findViewById(R.id.indicator);
    circlePageIndicator.setViewPager(viewPager);
}


class myPagerAdapter extends FragmentPagerAdapter {
    ArrayList <Fragment> fragmentList = new ArrayList<Fragment>();
public myPagerAdapter(FragmentManager fm, ArrayList<Fragment> fragments) {
    super(fm);
    fragmentList.addAll(fragments);
}

@Override
public Fragment getItem(int i) {
    return fragmentList.get(i);
}

@Override
public int getCount() {
    return fragmentList.size(); //nothing implemented here yet...
}
}

注意： 我无法正确排列代码，因此请忽略错误的格式。