介绍
我有一个Book的活动,其中包含一个类型为“page”的arraylist,并处理我决定使用FragmentStatePagerAdapter的所有页面,其中我的一个片段包含一个页面.
我为寻呼机中的每个片段和父活动之间的通信创建了一个接口.我在这个接口中需要的方法是更新页面中显示的页面,所以我为父活动创建了工具,用于从片段接收数据的接口并将它们存储在页面中以保存在arraylist中.
每个片段都有一个EditText,用户可以在其中编写,我设置addTextChangedListener来捕获用户停止写入的时刻.
当用户停止在EditText中写入时,在onTextChanged()中,我调用activity father中实现的函数.
这是我的活动代码
public class BookEditorActivity implements BookEditorFragment.EditorFrToEditorActInterface {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.book_editor_activity);
Bundle extras = getIntent().getExtras();
b = (Book) extras.get("book");
setBookViewPager(b);
}
private void setBookViewPager(Book b) {
mBookViewPager = (ViewPager) findViewById(R.id.book_editor_pager);
mBookViewPagerAdapter = new BookViewPagerAdapter(getSupportFragmentManager(),b);
mBookViewPager.setAdapter(mBookViewPagerAdapter);
}
@Override
public void saveBookPageTextContent(String textContent) {
int current = mBookViewPager.getCurrentItem();
if (b.getPages().get(current) instanceof BookPageText) {
((BookPageText) b.getPages().get(current)).setContentPageText(textContent);
}
}
@Override
public void newBookPageText() {
int current = mBookViewPager.getCurrentItem();
BookPageText bookPageText = new BookPageText();
bookPageText.setContentPageText("");
b.getPages().add(b.getPages().size() - 1,bookPageText);
setIndicator(current + 1,b.getPages().size());
mBookViewPagerAdapter.notifyDataSetChanged();
}
}
这是片段代码
public class BookEditorFragment extends Fragment {
private EditorFrToEditorActInterface mCallback;
public interface EditorFrToEditorActInterface {
void newBookPageText();
void saveBookPageTextContent(String s);
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bundle pageContent = getArguments();
if (pageContent != null) {
page = pageContent.getParcelable("page");
}
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState) {
if (page instanceof BookPageText) {
BookPageText bookPage = (BookPageText) page;
mView = inflater.inflate(R.layout.book_page_text_fragment,container,false);
contentPage = (EditText) mView.findViewById(R.id.content_text);
String contentPageText = bookPage.getContentPageText();
contentPage.setText(contentPageText.isEmpty() ? "" : Html.fromHtml(contentPageText));
contentPage.addTextChangedListener(new TextWatcher() {
public void onTextChanged(CharSequence c,int start,int before,int count) {
mCallback.saveBookPageTextContent(c.toString());
}
public void beforeTextChanged(CharSequence c,int count,int after) {
}
public void afterTextChanged(Editable c) {
}
});
}
return mView;
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
try {
mCallback = (EditorFrToEditorActInterface) context;
} catch (ClassCastException e) {
throw new ClassCastException(context.toString()
+ " must implement NewPageInterface");
}
}
@Override
public void onDetach() {
mCallback = null;
super.onDetach();
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.editor_new_text:
mCallback.newBookPageText();
break;
}
}
}
这是FragmentStatePagerAdapter代码
public class BookViewPagerAdapter extends FragmentStatePagerAdapter {
private ArrayList<Object> bookPages = new ArrayList<>();
private final SparseArray<WeakReference<BookEditorFragment>> instantiatedFragments = new SparseArray<>();
public BookViewPagerAdapter(FragmentManager fm,Book b) {
super(fm);
this.bookPages = b.getPages();
}
@Override
public Fragment getItem(int position) {
Object page = bookPages.get(position);
Bundle pageContent = new Bundle();
if (page instanceof BookPageText) {
BookPageText bookPageText = (BookPageText) page;
pageContent.putParcelable("page",bookPageText);
}
BookEditorFragment fragment = new BookEditorFragment();
fragment.setArguments(pageContent);
return fragment;
}
@Override
public int getCount() {
return bookPages.size();
}
@Override
public Object instantiateItem(final ViewGroup container,final int position) {
final BookEditorFragment fragment = (BookEditorFragment) super.instantiateItem(container,position);
instantiatedFragments.put(position,new WeakReference<>(fragment));
return fragment;
}
@Override
public void destroyItem(final ViewGroup container,final int position,final Object object) {
instantiatedFragments.remove(position);
super.destroyItem(container,position,object);
}
@Nullable
public Fragment getFragment(final int position) {
final WeakReference<BookEditorFragment> wr = instantiatedFragments.get(position);
if (wr != null) {
return wr.get();
} else {
return null;
}
}
@Override
public int getItemPosition(Object object) {
int position = bookPages.indexOf(object);
return position == -1 ? POSITION_NONE : position;
}
}
由于代码长度,我删除了一些部分,如onClickListener,onPageSelectionListener和我正在创建的其他类型的页面.
问题
这个逻辑似乎工作正常,但每次我修改片段中EditText的内容时,左边的close片段也会更新,我不知道为什么.
正如你在图像中看到的那样,如果我在EditText2中写一些东西,EditText1中会出现相同的内容,这没有任何意义.
另一个问题是,当我在书中添加新页面时,页面是正确创建的,但是使用上一页的内容,这没有任何意义. (再次！)
我的尝试
1)我试图捕获onFocusChange而不是使用addTextChangedListener,但没有改变.
2)我尝试使用onChangePageListener()实现不同的逻辑,但在这种情况下,我松开了mBookViewPager.getCurrentItem(),因此更新出错了.
3)我尝试了所有这些帖子：one,two,three和four.
我怎样才能纠正这种奇怪的行为？
是否有可能问题出现在我引用本书ArrayList中的页面的方式中？
谢谢
解决方法
我在实现中发现的一些可能的错误是.
>管理当前页面构成工具
mViewPager.setOnPageChangeListener(new OnPageChangeListener() {
@Override
public void onPageSelected(int p) {
current = p;
Log.e("Postion","" + p);
}
@Override
public void onPageScrolled(int arg0,float arg1,int arg2) {}
@Override
public void onPageScrollStateChanged(int arg0) {}
});
> viewpager自动加载私有和下一个视图
通过调用mathod来设置寻呼机OffscreenPageLimit
mViewPager.setOffscreenPageLimit();
>总是确保如果你在适配器中使用if语句,你应该通过else语句将它的计数器部分放在任何默认值中.
if (page instanceof BookPageText) {
BookPageText bookPageText = (BookPageText) page;
pageContent.putParcelable("page",bookPageText);
}
