我正在使用RecyclerView来显示元素列表，您可以从该列表转到详细屏幕，即查看分页器片段。我的问题是我导航到的第一个元素（来自RecyclerView）显示不正确 - 它有NestedScrollView，我无法完全向下滚动。如果我向左或向右转到下一页，它们很好，它总是首先加载的。
我的适配器类正在关注;
public class ApodViewAdapter extends FragmentStatePagerAdapter {
private ArrayList<APOD> mDataset;
public ApodViewAdapter(FragmentManager fm, ArrayList<APOD> apodsList) {
super(fm);
setData(apodsList);
}
public void setData(ArrayList<APOD> apodsList){
if(apodsList!=null){
this.mDataset= apodsList;
notifyDataSetChanged();
}
}
@Override
public Fragment getItem(int position) {
return new ApodViewFragment().newInstance(mDataset.get(position), position);
}
@Override
public int getCount() {
return mDataset.size();
}
}
片段活动：
public class ApodViewFragment extends Fragment implements DataInterface, AppBarLayout.OnOffsetChangedListener {
private ImageView mApodImageView;
private TextView mTextView;
private Toolbar mToolbar;
private AppBarLayout mAppBarLayout;
private TextView mTitle;
private FrameLayout mContentFl;
private APOD mApodElement;
private static final String KEY_CONTENT = "ApodViewFragment:Content";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if ((savedInstanceState != null) && savedInstanceState.containsKey(KEY_CONTENT)) {
mApodElement = (APOD) savedInstanceState.getSerializable(KEY_CONTENT);
}
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putSerializable(KEY_CONTENT, mApodElement);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
ViewGroup rootView = (ViewGroup) inflater.inflate(
R.layout.fragment_apod_material, container, false);
mApodImageView = (ImageView) rootView.findViewById(R.id.apod_view_apod_iv);
mTextView = (TextView) rootView.findViewById(R.id.apod_view_text_tv);
mTitle = (TextView) rootView.findViewById(R.id.apod_fragment_title_tv);
mContentFl = (FrameLayout) rootView.findViewById(R.id.fragment_apod_fl);
mToolbar = (Toolbar) rootView.findViewById(R.id.toolbar);
mAppBarLayout = (AppBarLayout) rootView.findViewById(R.id.app_bar_layout);
mAppBarLayout.addOnOffsetChangedListener(this);
ViewTreeObserver vto = mContentFl.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
setHeroImageMaxHeight();
ViewTreeObserver obs = mContentFl.getViewTreeObserver();
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
obs.removeOnGlobalLayoutListener(this);
} else {
obs.removeGlobalOnLayoutListener(this);
}
}
});
setData();
return rootView;
}
public static ApodViewFragment newInstance(APOD apodElement, int position) {
ApodViewFragment fragment = new ApodViewFragment();
fragment.mApodElement = apodElement;
return fragment;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void saveData(APOD apodElement) {
}
@Override
public void readData() throws IOException {
}
private void setData() {
if(mApodElement.getMedia_type().equals("video")){
Picasso.with(getActivity()).load(R.drawable.videoplaceholder).into(mApodImageView);
}else{
Picasso.with(getActivity()).load(mApodElement.getUrl()).into(mApodImageView);
}
mTextView.setText(mApodElement.getExplanation());
mTitle.setText(mApodElement.getTitle());
}
private void setHeroImageMaxHeight(){
int screenHeight = ImageHelper.getDisplayHeight(getActivity());
mToolbar.getLayoutParams().height = screenHeight - mContentFl.getHeight();
mToolbar.requestLayout();
}
@Override
public void onOffsetChanged(AppBarLayout appBarLayout, int offset) {
float minimalTextSize = getActivity().getResources().getDimensionPixelSize(R.dimen.apod_view_title_scrolling_text_size);
float maximumTextSize = getActivity().getResources().getDimensionPixelSize(R.dimen.apod_view_title_default_text_size);
float absolut_offset = Math.abs(offset);
float text_size_difference = maximumTextSize - minimalTextSize;
float scale = (absolut_offset) / (appBarLayout.getHeight() - absolut_offset);
if (offset < 0) {
float result = maximumTextSize - (scale * text_size_difference);
mTitle.setTextSize(FontHelper.pixelsToSp(getActivity(), result));
} else {
mTitle.setTextSize(FontHelper.pixelsToSp(getActivity(), maximumTextSize));
}
}
}
和XML布局文件
<android.support.design.widget.CollapsingToolbarLayout
android:id="@+id/apod_fragment_ctl"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_scrollFlags="scroll|exitUntilCollapsed"
app:expandedTitleMarginStart="16dp"
android:fitsSystemWindows="true">
<ImageView
android:id="@+id/apod_view_apod_iv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scaleType="centerCrop"
android:fitsSystemWindows="true"
app:layout_collapseMode="parallax"/>
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light">
<RelativeLayout
android:layout_width="wrap_content"
android:fitsSystemWindows="true"
android:layout_height="wrap_content">
<TextView
android:id="@+id/apod_fragment_title_tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="@android:color/white"
android:textSize="@dimen/apod_view_title_default_text_size"
android:layout_alignParentBottom="true"
app:layout_collapseMode="pin"
/>
</RelativeLayout>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:id="@+id/scroll"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:clipToPadding="false"
android:background="@android:color/holo_purple"
android:fitsSystemWindows="true"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<FrameLayout
android:id="@+id/fragment_apod_fl"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.CardView
android:id="@+id/cardview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="8dp"
android:layout_gravity="center_vertical"
app:cardUseCompatPadding="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/title"
android:text="TITLE"
android:layout_width="match_parent"
android:layout_height="wrap_content" android:textAppearance="@style/TextAppearance.AppCompat.Headline"/>
<TextView
android:id="@+id/apod_view_text_tv"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:textAppearance="@style/TextAppearance.AppCompat.Body1"/>
</LinearLayout>
</android.support.v7.widget.CardView>
</FrameLayout>
</android.support.v4.widget.NestedScrollView>
<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
app:layout_anchor="@id/cardview"
app:layout_anchorGravity="top|right|end"
android:src="@drawable/ic_rocket_em_blank"
android:layout_margin="16dp"
app:backgroundTint="@android:color/holo_purple"
style="@style/FabStyle"/>
</android.support.design.widget.CoordinatorLayout>
我会说原因必须在Adapter或fragment的方法中，它会创建新的Fragment，但却找不到它。任何帮助赞赏，欢呼！