我在tablayout / viewpager中的片段之间传递数据时遇到问题。我有一个带有四个选项卡的Tablayout，并使用viewpager启用了切换。我正在尝试从FirstTabFragment，SecondTabFragment和ThirdTabFragment中保存数据，并在最后一个选项卡= ReviewFragment中检索它们。我已经实现了将数据保存到SharedPreferences中的功能，这适用于第一个和第二个片段，第三个片段中的数据没有保存，打开ReviewFragment时显示为空。
FirstFragment是一个Listview，将保存所选listview项目中的字符串。
SecondFragment是一个editText，按下下一个按钮时将保存输入的值。
ThirdFragment也是一个Listview，FirstFragment中的代码与此片段相同，但无法按预期工作。
我的意思是无法按预期工作：在ThirdFragment中的值实际上已保存到SharedPreferences中，但在打开ReviewFragment时不会立即检索到。我知道这一点是因为当我关闭应用程序并重新打开它时，它显示了SharedPreferences中保存的值。
下面是我来自ThirdFragment和ReviewFragment的代码
第三片段
private SharedPreferences memory1;
private SharedPreferences.Editor edt1;
private ListView listView;
private ArrayAdapter<String> listAdapter;
public MtnPaymentMtdFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.payment_method, container, false);
// Find the ListView resource.
listView = (ListView) v.findViewById(R.id.mtn_plv);
// Create and populate a List
String[] p_method = new String[]{"ATM - MasterCard - Visa - Verve", "Online Bank Transfer", "Bank Deposit", "Recharge Card", "Mobile Banking"};
ArrayList<String> p_methods = new ArrayList<String>();
p_methods.addAll(Arrays.asList(p_method));
// Create ArrayAdapter using the list.
listAdapter = new ArrayAdapter<String>(this.getActivity(), R.layout.item_row3, p_methods);
// Set the ArrayAdapter as the ListView's adapter.
listView.setAdapter(listAdapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
String selectedFromList = (listView.getItemAtPosition(i).toString().trim());
switch (i) {
case 0:
MtnReviewFragment fragment = new MtnReviewFragment();
Bundle bundler = new Bundle();
bundler.putString("payment_mtd", selectedFromList);
fragment.setArguments(bundler);
// memory1 = getActivity().getPreferences(0);
// edt1 = memory1.edit();
// edt1.putString("payment_mtd", selectedFromList);
// edt1.apply();
((MtnActivity) getActivity()).setCurrentItem(3, true);
break;
case 1:
// String selectedFromList1 = (listView.getItemAtPosition(i).toString().trim());
memory1 = getActivity().getPreferences(0);
edt1 = memory1.edit();
edt1.putString("payment_mtd", selectedFromList);
edt1.apply();
((MtnActivity) getActivity()).setCurrentItem(3, true);
break;
case 2:
// String selectedFromList2 = (listView.getItemAtPosition(i).toString().trim());
memory1 = getActivity().getPreferences(0);
edt1 = memory1.edit();
edt1.putString("payment_mtd", selectedFromList);
edt1.apply();
((MtnActivity) getActivity()).setCurrentItem(3, true);
break;
case 3:
// String selectedFromList3 = (listView.getItemAtPosition(i).toString().trim());
memory1 = getActivity().getPreferences(0);
edt1 = memory1.edit();
edt1.putString("payment_mtd", selectedFromList);
edt1.apply();
((MtnActivity) getActivity()).setCurrentItem(3, true);
break;
case 4:
// String selectedFromList4 = (listView.getItemAtPosition(i).toString().trim());
memory1 = getActivity().getPreferences(0);
edt1 = memory1.edit();
edt1.putString("payment_mtd", selectedFromList);
edt1.apply();
((MtnActivity) getActivity()).setCurrentItem(3, true);
}
}
});
return v;
}
}
评论片段
private SharedPreferences memory;
private SharedPreferences.Editor edt;
private TextView rev_bundle_result;
private TextView rev_mob_result;
private TextView rev_pmtd_result;
public static SharedPreferences savedSharedPreference;
public static String filename = "nameValue";
private static final String REGISTER_URL = "http://zzzzzzzzz.com/xxxxx/register.php";
public MtnReviewFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.review_layout, container, false);
rev_bundle_result = (TextView) v.findViewById(R.id.rev_bundle_result);
rev_mob_result = (TextView) v.findViewById(R.id.rev_mob_result);
rev_pmtd_result = (TextView) v.findViewById(R.id.rev_pmtd_result);
Button make_payment = (Button) v.findViewById(R.id.make_payment_but);
memory = getActivity().getPreferences(0);
String bundles = memory.getString("bundle_name", "empty");
String mob_number = memory.getString("mob_number", "empty");
String payment_mtds = memory.getString("payment_mtd", "empty");
String p_amount = memory.getString("amount", "empty");
rev_bundle_result.setText(bundles);
rev_mob_result.setText(mob_number);
rev_pmtd_result.setText(payment_mtds);
最佳答案
这有点旧，您可能已经找到了解决方案，但是以防万一其他人到了这里并需要答案...
我认为您的问题可能是因为在ReviewFragment中，您是通过onCreateView（）方法中的SharedPreferences获取数据的。
当您滚动到ThirdFragment时，可能正在创建您的ReviewFragment。 ViewPagers通常会提前创建一些片段，以提高用户滚动时的性能。因此，当调用ReviewFragment.onCreateView（）时，ThirdFagment尚未将其数据保存到SharedPreferences中。在您的ReviewFragment.onCreateView（）中添加一个断点，并检查是否发生了这种情况。
我认为您仅在可见时才需要向ViewPager添加OnPageChangeListener并使ReviewFragment从SharedPreferences中获取数据。另外，请检出Fragment.setUserVisibleHint（）。它曾经不能与ViewPagers一起正常使用，但是我已经知道该问题已得到解决。