每次滑动都会清除ViewPager中碎片的数据

Question

@Override
public void onViewDetachedFromWindow(@NonNull FragmentViewHolder holder) {
super.onViewDetachedFromWindow(holder);
}

我有许多独立的EditText，在viewpager的每个片段中都有不同的id。对于每次滑动，我都想清除这些EditText并将其设为默认值。

我可以使用清除文本

holder.itemview.findViewById(R.id.first).setText("something");

但它不会是一个清晰的文本。

我该怎么办？

编辑：整个测试代码：我准备了一个测试片段。当我点击按钮时，它会更改当前片段中的文本。当我滑动到第二个片段时，它应该被清除或更改为xml中的默认值。

测试片段

public class TestFragment extends Fragment {
private TestViewModel mViewModel;
private ViewPager2 mViewPager;
private Button btnTest;
public static TestFragment newInstance() {
return new TestFragment();
}
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
@Nullable Bundle savedInstanceState) {
View view=inflater.inflate(R.layout.test_fragment, container, false);
btnTest=(Button)view.findViewById(R.id.etTest);
return view;
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mViewModel = ViewModelProviders.of(this).get(TestViewModel.class);

}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mViewPager = view.findViewById(R.id.myPager);
mViewPager.setSaveFromParentEnabled(false);
mViewPager.setOffscreenPageLimit(1);
mViewPager.setAdapter(new ViewPagerAdapter(getChildFragmentManager(),getLifecycle()));
TabLayout tabLayout = view.findViewById(R.id.tabs);
new TabLayoutMediator(tabLayout, mViewPager,
new TabLayoutMediator.TabConfigurationStrategy() {
@Override
public void onConfigureTab(@NonNull TabLayout.Tab tab, int position) {
tab.setText(((ViewPagerAdapter)(mViewPager.getAdapter())).mFragmentNames[position]);//Sets tabs names as mentioned in ViewPagerAdapter fragmentNames array, this can be implemented in many different ways.
}
}
).attach();
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
Fragment current=((ViewPagerAdapter)(mViewPager.getAdapter())).createFragment(tab.getPosition());//clear data here or below
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}});
btnTest.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
int cur=((ViewPagerAdapter)(mViewPager.getAdapter())).getCurrentPos();
switch (cur){
case 0:
Fragment current=((ViewPagerAdapter)(mViewPager.getAdapter())).createFragment(0);
TextView tF= current.getView().findViewById(R.id.first);
tF.setText("Clicked while 1");
break;
case 1:
Fragment current2=((ViewPagerAdapter)(mViewPager.getAdapter())).createFragment(1);
TextView tF2= current2.getView().findViewById(R.id.second);
tF2.setText("Clicked while 2");
break;
}
}
});

}
public class ViewPagerAdapter extends FragmentStateAdapter {
private int currentPos;
private final Fragment[] mFragments = new Fragment[] {
new FirstFragment(),
new SecondFragment(),
};
public final String[] mFragmentNames = new String[] {
"First",
"Second"
};
public ViewPagerAdapter(@NonNull FragmentManager fragmentManager, @NonNull Lifecycle lifecycle) {
super(fragmentManager, lifecycle);
}

@Override
public void onViewDetachedFromWindow(@NonNull FragmentViewHolder holder) {
super.onViewDetachedFromWindow(holder);
if(currentPos!=0){
TextView textView =(TextView)holder.itemView.findViewById(R.id.first);//clear data here or up
}
}
@Override
public int getItemCount() {
return mFragments.length;
}
@Override
public long getItemId(int position) {
this.setCurrentPos(position);
return super.getItemId(position);
}

public int getCurrentPos() {
return currentPos;
}
public void setCurrentPos(int currentPos) {
this.currentPos = currentPos;
}
@NonNull
@Override
public Fragment createFragment(int position) {
return mFragments[position];
}
}}

我可以处理onViewDetachedFromWindow或onTabUnselected。两者都可以更改视图。

第一片段

public class FirstFragment extends Fragment {
private View mLeak;
private TextView tvTest;
public FirstFragment() {
}
public static FirstFragment newInstance(String param1, String param2) {
FirstFragment fragment = new FirstFragment();
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mLeak = inflater.inflate(R.layout.fragment_first, container, false);
tvTest=mLeak.findViewById(R.id.first);
return mLeak;
}
@Override
public void onDetach() {
super.onDetach();
mLeak=null;
}}

Answer 1

方法1:

在你的寻呼机上设置这一行：

viewPager.setOffscreenPageLimit(1);

这将只是在加载每个片段时再次刷新它。

方法2:

创建一个接口并在每个片段上实现它。在定义了viewpager的活动/片段中，使用"；addOnPageChangeListener"；在viewpager上，当选择不同的页面时，只需使用接口返回片段实例并调用片段中所需的方法，即可清除/更改文本。

代码：

//Your Activity
class HomeActivity extends Activity{
...Methods...
public void setUpViewpager(){
//setup your viewpager  
viewpager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}
@Override
public void onPageSelected(int position) {
ChangeText fragment = (ChangeText) viewpager.getFragment(position);
fragment.changeText();
}
@Override
public void onPageScrollStateChanged(int state) {}

});
}
interface ChangeText{
void changeText();
}
}
//Your fragment
class FirstFragment extends Fragment implements HomeActivity.ChangeText{

...Methods...
public void changeText(){
//change the textview text here
}
}
class SecondFragment extends Fragment implements HomeActivity.ChangeText{

...Methods...
public void changeText(){
//change the textview text here
}
}