我有以下问题：当我点击按钮时，我想要从MyListFragment传递参数到FragmentTwo;但是我所拥有的代码并不起作用......我不知道为什么......我希望你能帮助我！ 感谢
public class ScrollableTabsActivity extends AppCompatActivity {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_scrollable_tabs);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFrag(new MyListFragment(),"PIZZE");
adapter.addFrag(new TwoFragment(), "TWO");
adapter.addFrag(new ThreeFragment(), "THREE");
adapter.addFrag(new FourFragment(), "FOUR");
adapter.addFrag(new FiveFragment(), "FIVE");
adapter.addFrag(new SixFragment(), "SIX");
adapter.addFrag(new SevenFragment(), "SEVEN");
adapter.addFrag(new EightFragment(), "EIGHT");
adapter.addFrag(new NineFragment(), "NINE");
adapter.addFrag(new TenFragment(), "TEN");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
@Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
@Override
public int getCount() {
return mFragmentList.size();
}
public void addFrag(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
@Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}
MY FRAGMENT LIST：
public class MyListFragment extends Fragment implements
android.widget.CompoundButton.OnCheckedChangeListener {
ListView lv;
ArrayList<Planet> planetList;
PlanetAdapter plAdapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.fragment_list2, container, false);
Button mButton = (Button) rootView.findViewById(R.id.button);
mButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
showResult(v);
}
});
//return inflater.inflate(R.layout.fragment_list2, container, false);
return rootView;
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
lv = (ListView)getView().findViewById(R.id.listview);
displayPlanetList();
}
private void displayPlanetList() {
planetList = new ArrayList<Planet>();
planetList.add(new Planet("Margherita", 6, "€"));
planetList.add(new Planet("Diavola", 7,"€"));
planetList.add(new Planet("Bufalina", 5,"€"));
planetList.add(new Planet("Marinara", 5,"€"));
planetList.add(new Planet("Viennese", 4,"€"));
plAdapter = new PlanetAdapter(planetList, getContext()) {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
int pos = lv.getPositionForView(buttonView);
if (pos != ListView.INVALID_POSITION) {
Planet p = planetList.get(pos);
p.setSelected(isChecked);
/*Toast.makeText(
getActivity(),
"Clicked on Pizza: " + p.getName() + ". State: is "
+ isChecked, Toast.LENGTH_SHORT).show();*/
}
}
};
lv.setAdapter(plAdapter);
}
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
/*int pos = lv.getPositionForView(buttonView);
if (pos != ListView.INVALID_POSITION) {
Planet p = planetList.get(pos);
p.setSelected(isChecked);
*//*Toast.makeText(
getActivity(),
"Clicked on Planet: " + p.getName() + ". State: is "
+ isChecked, Toast.LENGTH_SHORT).show();*//*
}*/
}
public void showResult(View v) {
String result = "Selected Product are :";
int totalAmount=0;
String b="";
for (Planet p : plAdapter.getBox()) {
if (p.selected){
result += "\n" + p.name+" "+p.distance+"€"+"q.tà :"+p.getQuantità();
int quantitaInt= Integer.parseInt(p.getQuantità() );
totalAmount+=p.distance * quantitaInt;
b=String.valueOf(totalAmount);
}
}
// Toast.makeText(getActivity(), result + "\n" + "Total Amount:=" + totalAmount+"€", Toast.LENGTH_LONG).show();
Fragment fragment = new Fragment();
Bundle bundle = new Bundle();
bundle.putString("totale", b);
fragment.setArguments(bundle);
}
}
FRAGMENT TWO：
public class TwoFragment extends Fragment{
public TwoFragment() {
// 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 rootView = inflater.inflate(R.layout.fragment_two, container, false);
TextView titolo2 = (TextView)rootView.findViewById(R.id.quantità2);
Bundle bundle=getArguments();
String myInt = bundle.getString("totale", null);
titolo2.setText(myInt);
return rootView;
}
}
logcat的：
05-05 10:00:59.476 14753-14753/info.androidhive.materialtabs E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.NullPointerException
at info.androidhive.materialtabs.fragments.TwoFragment.onCreateView(TwoFragment.java:32)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1974)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1252)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:742)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1617)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:570)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1177)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1025)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1545)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:668)
at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:735)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1369)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:660)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:553)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1369)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:660)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:553)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2092)
at android.view.View.measure(View.java:12723)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1064)
at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2442)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4424)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：1)
试试这个!!!
public class TwoFragment extends Fragment{
public TwoFragment() {
// 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 rootView = inflater.inflate(R.layout.fragment_two, container, false);
TextView titolo2 = (TextView)rootView.findViewById(R.id.quantità2);
Bundle bundle=getArguments();
if(bundle != null){
String myInt = bundle.getString("totale", null);
titolo2.setText(myInt);
}
return rootView;
}
}
OneFragment
public void showResult(View v) {
String result = "Selected Product are :";
int totalAmount=0;
String b="";
for (Planet p : plAdapter.getBox()) {
if (p.selected){
result += "\n" + p.name+" "+p.distance+"€"+"q.tà :"+p.getQuantità();
int quantitaInt= Integer.parseInt(p.getQuantità() );
totalAmount+=p.distance * quantitaInt;
b=String.valueOf(totalAmount);
}
}
// Toast.makeText(getActivity(), result + "\n" + "Total Amount:=" + totalAmount+"€", Toast.LENGTH_LONG).show();
Bundle bun = new Bundle();
bun.putString("totale", b);
TwoFragment fgsearch = new TwoFragment();
fgsearch.setArguments(bun);
android.support.v4.app.FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.content_main, fgsearch);
transaction.commit();
}
当replace fragment将FrameLayout更改为two_fragment.xml
时<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/frame_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:id="@+id/content_main"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
答案 1 :(得分：0)
我认为您的问题在线指出
TextView titolo2 = (TextView)rootView.findViewById(R.id.quantità2);
Bundle bundle=getArguments();
String myInt = bundle.getString("totale", null);<---- here remove the null
//argument do it like this below
String myInt = bundle.getString("totale")
titolo2.setText(myInt);