我有一个带有两个片段的MainActivity。第二个片段有RecyclerView。在RecyclerView中有TextView（课程名称）和ImageView（显示课程状态，如果已完成或未完成）。单击TextView时，它会通过课程调用另一个Activity。完成课程后，您将返回MainActivity。在那之后，ImageView将从零改为资源'ic_lessondone'。 MainActivity中还有一个菜单。菜单包含“重置课程”项目。按“重置课程”时，所有ImageView都不会显示任何图像。所以有两个问题。 1）如果我这样做，例如，只有第6课。我会把图像'少一些'。当我按下“重置课程”时，图像将消失。但当我再次返回菜单并按“重置课程”时，图像将再次出现并上升到上一课（第5节）。 2）如果我关闭显示，图像也会出现在上一课，直到0。 看来我的onResume有问题。 请帮帮我。
public class MainActivity extends AppCompatActivity
{
private DrawerLayout mDrawerLayout;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
final ActionBar ab = getSupportActionBar();
ab.setHomeAsUpIndicator(R.drawable.ic_menu);
ab.setDisplayHomeAsUpEnabled(true);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
if (navigationView != null)
{
setupDrawerContent(navigationView);
}
ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
if (viewPager != null)
{
setupViewPager(viewPager);
}
// Круглая кнопка
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view)
{
Snackbar.make(view, "Here's a Snackbar", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
// Картинки для табов
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
tabLayout.getTabAt(0).setIcon(R.drawable.ic_home);
tabLayout.getTabAt(1).setIcon(R.drawable.ic_lessons);
}
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
getMenuInflater().inflate(R.menu.sample_actions, menu);
return true;
}
@Override
public boolean onPrepareOptionsMenu(Menu menu)
{
switch (AppCompatDelegate.getDefaultNightMode())
{
case AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM:
menu.findItem(R.id.menu_night_mode_system).setChecked(true);
break;
case AppCompatDelegate.MODE_NIGHT_AUTO:
menu.findItem(R.id.menu_night_mode_auto).setChecked(true);
break;
case AppCompatDelegate.MODE_NIGHT_YES:
menu.findItem(R.id.menu_night_mode_night).setChecked(true);
break;
case AppCompatDelegate.MODE_NIGHT_NO:
menu.findItem(R.id.menu_night_mode_day).setChecked(true);
break;
}
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
switch (item.getItemId())
{
case android.R.id.home:
mDrawerLayout.openDrawer(GravityCompat.START);
return true;
case R.id.menu_night_mode_system:
setNightMode(AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM);
break;
case R.id.menu_night_mode_day:
setNightMode(AppCompatDelegate.MODE_NIGHT_NO);
break;
case R.id.menu_night_mode_night:
setNightMode(AppCompatDelegate.MODE_NIGHT_YES);
break;
case R.id.menu_night_mode_auto:
setNightMode(AppCompatDelegate.MODE_NIGHT_AUTO);
break;
}
return super.onOptionsItemSelected(item);
}
private void setNightMode(@AppCompatDelegate.NightMode int nightMode)
{
AppCompatDelegate.setDefaultNightMode(nightMode);
if (Build.VERSION.SDK_INT >= 11)
{
recreate();
}
}
private void setupViewPager(ViewPager viewPager)
{
Adapter adapter = new Adapter(getSupportFragmentManager());
adapter.addFragment(new Fragment(), "");
adapter.addFragment(new LessonsListFragment(), "");
viewPager.setAdapter(adapter);
}
// Главное меню
private void setupDrawerContent(NavigationView navigationView)
{
navigationView.setNavigationItemSelectedListener(
new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(MenuItem menuItem)
{
menuItem.setChecked(true);
if (menuItem.getTitle().equals("Reset lessons"))
{
// Обнуляем файл с рузультатами уроков
LessonsListFragment.sLessonsPref.edit().clear().commit();
// Перерисовываем весь писок уроков
LessonsListFragment.rv.getAdapter().notifyItemRangeChanged(0, LessonsListFragment.rv.getAdapter().getItemCount());
}
mDrawerLayout.closeDrawers();
return true;
}
});
}
static class Adapter extends FragmentPagerAdapter
{
private final List<Fragment> mFragments = new ArrayList<>();
private final List<String> mFragmentTitles = new ArrayList<>();
public Adapter(FragmentManager fm)
{
super(fm);
}
public void addFragment(Fragment fragment, String title)
{
mFragments.add(fragment);
mFragmentTitles.add(title);
}
// Получаем конкретный фрагмент
@Override
public Fragment getItem(int position)
{
return mFragments.get(position);
}
// Количество фрагментов для viewpager (2)
@Override
public int getCount()
{
return mFragments.size();
}
@Override
public CharSequence getPageTitle(int position)
{
return mFragmentTitles.get(position);
}
}
}
片段
public class LessonsListFragment extends Fragment
{
// Уроки
// static private Map<String,?> mLessonsKeys ;
static SharedPreferences sLessonsPref;
static RecyclerView rv;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
loadSharedPreferenses();
rv = (RecyclerView) inflater.inflate(R.layout.fragment_cheese_list, container, false);
setupRecyclerView(rv);
return rv;
}
// Загружаем список пройденных уроков
public void loadSharedPreferenses()
{
sLessonsPref = this.getActivity().getSharedPreferences("LessonsResults", Context.MODE_PRIVATE);
}
// Количество строк в листе
private void setupRecyclerView(RecyclerView recyclerView)
{
recyclerView.setLayoutManager(new LinearLayoutManager(recyclerView.getContext()));
recyclerView.setAdapter(new SimpleStringRecyclerViewAdapter(getActivity(), getRandomSublist(Cheeses.sCheeseStrings, Cheeses.sCheeseStrings.length)));
}
// Задаем Строки
private List<String> getRandomSublist(String[] array, int amount)
{
ArrayList<String> list = new ArrayList<>(amount);
//Random random = new Random();
while (list.size() < amount)
{
list.add(array[list.size()]);
}
return list;
}
//Отработка перерисования окна, при возврате к ней
@Override
public void onResume()
{
super.onResume();
//loadSharedPreferenses();
//Toast.makeText(null, "Refreshed", Toast.LENGTH_SHORT).show();
if (rv.getAdapter() != null)
{
rv.getAdapter().notifyDataSetChanged();
}
}
// Адаптер
public static class SimpleStringRecyclerViewAdapter
extends RecyclerView.Adapter<SimpleStringRecyclerViewAdapter.ViewHolder>
{
private final TypedValue mTypedValue = new TypedValue();
private int mBackground;
private List<String> mValues;
public static class ViewHolder extends RecyclerView.ViewHolder
{
// Номер урока, передается в webactivity
public int mLessonNumber;
public final View mView;
public final ImageView mImageView;
public final TextView mTextView;
public ViewHolder(View view)
{
super(view);
mView = view;
mImageView = (ImageView) view.findViewById(R.id.avatar);
mTextView = (TextView) view.findViewById(android.R.id.text1);
}
@Override
public String toString()
{
return super.toString() + " '" + mTextView.getText();
}
}
public String getValueAt(int position)
{
return mValues.get(position);
}
public SimpleStringRecyclerViewAdapter(Context context, List<String> items)
{
context.getTheme().resolveAttribute(R.attr.selectableItemBackground, mTypedValue, true);
mBackground = mTypedValue.resourceId;
mValues = items;
}
// Создаем холдер с полезной нагрузкой
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item, parent, false);
view.setBackgroundResource(mBackground);
return new ViewHolder(view);
}
//Создаем список уроков
@Override
public void onBindViewHolder(final ViewHolder holder, int position)
{
holder.mLessonNumber = position + 1;
// Увеличиваем позицион на 1 что не было 0 урока
holder.mTextView.setText((position + 1) + " " + mValues.get(position));
// Если урок пройден
String finished = sLessonsPref.getString((position + 1) + "", "");
if (finished.equals("1"))
{
// Меняем его цвет
//holder.mTextView.setTextColor(R.color.white);
Glide.with(holder.mImageView.getContext()).load(R.drawable.ic_lessondone)
//.load(Cheeses.getRandomCheeseDrawable())
.fitCenter()
.into(holder.mImageView);
Log.d("Glide", "Work");
}
else
{
holder.mTextView.setTextColor(R.color.black);
// holder.mImageView.setVisibility(View.GONE);
}
// Вызов WebActivity
holder.mView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
{
Context context = v.getContext();
Intent intent = new Intent(context, WebActivity.class);
// Передаем вебвью номер урока и запускаем ее
intent.putExtra(WebActivity.EXTRA_NAME, holder.mLessonNumber);
context.startActivity(intent);
}
});
}
// Определяем количество выводимых строк
@Override
public int getItemCount()
{
return mValues.size();
}
}
}
答案 0 :(得分：0)
在适配器中实现一个reset()方法，将所有项目标记为＆＃34;未完成＆＃34;然后尝试：
LessonsListFragment.rv.getAdapter().reset();
LessonsListFragment.rv.getAdapter().notifyDataSetChanged();
而不是：
LessonsListFragment.rv.getAdapter().notifyItemRangeChanged(0, LessonsListFragment.rv.getAdapter().getItemCount());
在onNavigationItemSelected内。
此外，你不应该使用静态变量（如static RecyclerView rv），使用private变量与吸气剂
答案 1 :(得分：0)
问题出在其他声明中。我在那里添加了这段代码，现在还可以。 notifydatachanged在导航视图中正常工作
if (finished.equals("1"))
{
// Меняем его цвет
//holder.mTextView.setTextColor(R.color.white);
Glide.with(holder.mImageView.getContext()).load(R.drawable.ic_lessondone)
.fitCenter()
.into(holder.mImageView);
Log.d("Glide", "Work");
}
else
{
Glide.with(holder.mImageView.getContext()).load(R.color.white)
.fitCenter()
.into(holder.mImageView);
holder.mTextView.setTextColor(R.color.black);
}