嗨，我是android片段的新手。我想从ViewPager中添加片段中的值。但我不知道如何正确地做到这一点？它给了我错误java.lang.NullPointerException，我试图看到引用，但我找不到如何以正确的方式执行此操作的示例。谢谢
private void setupViewPager(ViewPager viewPager) {
adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFrag(new Inspection_JTM_Fragment_Inspeksi_Tab(), getString(R.string.inspection_jtm_title_tab_03));
viewPager.setAdapter(adapter);
}
然后检索值并使用
保存public boolean onOptionsItemSelected(MenuItem item) {
final int id = item.getItemId();
if (id == R.id.action_upload) {
saveData();
return true;
return super.onOptionsItemSelected(item);
}
private void saveData() {
Saran = Inspection_JTM_Fragment_Inspeksi_Tab.getSaran();
keterangan = Inspection_JTM_Fragment_Inspeksi_Tab.getketerangan();
details.setSaran(Saran);
details.setketerangan(keterangan);
if (action_flag.equals("add")) {
databaseHandler.create(details);
}
}
public class Inspection_JTM_Fragment_Inspeksi_Tab extends Fragment implements LocationListener, View.OnClickListener, TextWatcher {
static String saran = "";
static String keterangan = "";
private static EditText editTextSaran;
private static EditText editTextKeterangan;
public Inspection_JTM_Fragment_Inspeksi_Tab() {
// Required empty public constructor
}
public static String getSaran() {
return saran;
}
public static String getketerangan() {
return keterangan;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
context = getActivity();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
view = inflater.inflate(R.layout.inspection_jtm_fragment_tab_inspeksi, container, false);
databaseHandler = new DatabaseHandler(getActivity());
editTextSaran = (EditText) view.findViewById(R.id.et_saran_saran_jtm_inspeksi);
editTextKeterangan = (EditText) view.findViewById(R.id.et_keterangan_jtm_inspeksi);
editTextSaran.addTextChangedListener(this);
editTextKeterangan.addTextChangedListener(this);
return view;
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
Inspection_JTM_Fragment_Inspeksi_Tab.this.updateValue();
}
private void updateValue() {
saran = editTextSaran.getText().toString();
keterangan = editTextKeterangan.getText().toString();
}
@Override
public void afterTextChanged(Editable s) {
}
}
logcat的：
FATAL EXCEPTION: main
Process: id.co.bumisentosa.yantek, PID: 23364
java.lang.NullPointerException
at id.co.bumisentosa.yantek.activity.InspectionMVActivityTabs.saveData(InspectionMVActivityTabs.java:325)
at id.co.bumisentosa.yantek.activity.InspectionMVActivityTabs.onOptionsItemSelected(InspectionMVActivityTabs.java:206)
at android.app.Activity.onMenuItemSelected(Activity.java:2600)
at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:361)
at android.support.v7.app.AppCompatActivity.onMenuItemSelected(AppCompatActivity.java:147)
at android.support.v7.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:100)
at android.support.v7.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:100)
at android.support.v7.app.ToolbarActionBar$2.onMenuItemClick(ToolbarActionBar.java:68)
at android.support.v7.widget.Toolbar$1.onMenuItemClick(Toolbar.java:172)
at android.support.v7.widget.ActionMenuView$MenuBuilderCallback.onMenuItemSelected(ActionMenuView.java:760)
at android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:811)
at android.support.v7.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:152)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:958)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:948)
at android.support.v7.widget.ActionMenuView.invokeItem(ActionMenuView.java:618)
at android.support.v7.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:139)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method