共享首选项和onPause不工作 [英] shared preferences and onPause doesn't work
本文介绍了共享首选项和onPause不工作的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
如果我检查一个复选框，进入选项卡没有列表视图与复选框，并进入上一个选项卡，我看到复选框之前...但如果我点击另一个选项卡列表视图与复选框，我的程序崩溃...为什么？
现在我发布我的代码...
我希望你可以帮助我！
提前感谢！
ADAPTER CLASS：
public abstract class PlanetAdapter extends ArrayAdapter& implements CompoundButton.OnCheckedChangeListener {
private List< Planet> planetList;
private上下文上下文;
ArrayList< Birra>对象;
public PlanetAdapter（List< Planet> planetList，Context context）{
super（context，R.layout.single_listview_item，planetList）;
this.planetList = planetList;
this.context = context;
}
public class PlanetHolder {
public TextView planetName;
public TextView distView;
public TextView valuta;
public CheckBox chkBox;
public EditText edit;
public Stringquantità;
}
@Override
public View getView（final int position，View convertView，ViewGroup parent）{
View row = convertView;
PlanetHolder holder = null;
if（row == null）{
LayoutInflater inflater =（（Activity）context）.getLayoutInflater（）;
row = inflater.inflate（R.layout.single_listview_item，parent，false）;
holder = new PlanetHolder（）;
holder.planetName =（TextView）row.findViewById（R.id.name）;
holder.distView =（TextView）row.findViewById（R.id.dist）;
holder.valuta =（TextView）row.findViewById（R.id.valuta）;
holder.chkBox =（CheckBox）row.findViewById（R.id.chk_box）;
holder.edit =（EditText）row.findViewById（R.id.editText）;
holder.edit.setVisibility（View.GONE）;
holder.edit.setEnabled（false）;
row.setTag（holder）;
} else {
holder =（PlanetHolder）row.getTag（）;
}
final Planet p = planetList.get（position）;
final PlanetHolder finalHolder = holder;
/ * SharedPreferences preferences = getContext（）。getSharedPreferences（MaterialTabs，android.content.Context.MODE_PRIVATE）;
boolean mCheckBoxValue = preferences .getBoolean（CheckBox_Value，false）;
if（mCheckBoxValue）{
holder.chkBox.setChecked（true）;
} else {
holder.chkBox.setChecked（false）;
} * /
holder.chkBox.setOnClickListener（new View.OnClickListener（）{
@Override
public void onClick（View v）{
if（finalHolder.chkBox.isChecked（））{
finalHolder.edit.setVisibility（View.VISIBLE）;
finalHolder.edit.setEnabled（true）;
SharedPreferences preferences = getContext getSharedPreferences（MaterialTabs，android.content.Context.MODE_PRIVATE）;
/ * SharedPreferences.Editor editor = preferences.edit（）;
editor.putBoolean（showActivity，finalHolder.chkBox.isChecked ）;
editor.commitmit（）; * /
// boolean value = true;
SharedPreferences.Editor mEditor = preferences.edit（）;
mEditor.putBoolean CheckBox_Value，finalHolder.chkBox.isChecked（））;
mEditor.commit（）;
finalHolder.edit.addTextChangedListener（new TextWatcher（）{
@覆盖
public void beforeTextChanged（CharSequence s，int start，int count，int after）{
}
@Override
public void onTextChanged（CharSequence s，int start ，int before，int count）{
}
@Override
public void afterTextChanged（可编辑）{
p.setQuantità（finalHolder.edit.getText .toString（）。trim（））;
/ * SharedPreferences preferences = getContext（）。getSharedPreferences（PROJECT_NAME，android.content.Context.MODE_PRIVATE）;
SharedPreferences.Editor editor = preferences.edit（）;
editor.putString（KEY，finalHolder.edit.getText（）。toString（）。trim（））;
editor.commitmit（）; * /
}
}）;
} else {
finalHolder.edit.setVisibility（View.GONE）;
finalHolder.edit.setEnabled（false）;
finalHolder.edit.setText（null）;
}
}
}）;
holder.planetName.setText（p.getName（））;
holder.distView.setText（+ p.getDistance（））;
holder.valuta.setText（+ p.getValuta（））;
holder.chkBox.setChecked（p.isSelected（））;
holder.chkBox.setTag（p）;
holder.edit.setEnabled（false）;
return row;
}
ArrayList< Planet> getBox（）{
ArrayList< Planet> box = new ArrayList< planet>（）;
for（Planet p：planetList）{
if（p.selected）
box.add（p）;
}
return box;
}
}
第一个FRAGMENT CLASS WITH LISTVIEW WITH CHECKBOX：
public class MyListFragment extends Fragment implements android.widget.CompoundButton.OnCheckedChangeListener {
ListView lv;
ArrayList< Planet> planetList;
PlanetAdapter plAdapter;
BirraAdapter biAdapter;
PlanetAdapter.PlanetHolder holder;
@Override
public查看onCreateView（LayoutInflater inflater，ViewGroup容器，
Bundle savedInstanceState）{
//扩充此片段的布局
ViewGroup rootView =（ViewGroup）inflater.inflate（R.layout.fragment_list2，container，false）;
按钮mButton =（Button）rootView.findViewById（R.id.button）;
mButton.setOnClickListener（new View.OnClickListener（）{
public void onClick（View v）{
showResult（v）;
} b $ b}）;
// 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&
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（），
点击Pizza：+ p.getName（）+。State：is
+ isChecked，Toast.LENGTH_SHORT）.show（）; * /
}
}
};
lv.setAdapter（plAdapter）;
}
@Override
public void onPause（）{
//获取实例变量
SharedPreferences preferences = getContext（）。 getSharedPreferences（MaterialTabs，android.content.Context.MODE_PRIVATE）;
boolean mCheckBoxValue = preferences.getBoolean（CheckBox_Value，false）;
if（mCheckBoxValue）{
holder.chkBox.setChecked（true）;
} else {
holder.chkBox.setChecked（false）;
}
super.onPause（）;
}
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（），
点击Planet：+ p.getName（）+。
+ isChecked，Toast.LENGTH_SHORT）.show（）; * // *
} * /
}
void showResult（View v）{
String result2 =所选产品是：;
int totalAmount2 = 0;
String a =;
for（Birra b：biAdapter.getBox（））{
if（b.selected）{
result2 + =\\\
+ b。 name ++ b.distance +€+q.tà：+b.getQuantità（）;
int quantitaInt = Integer.parseInt（b.getQuantità（））;
totalAmount2 + = b.distance * quantitaInt;
//a=String.valueOf(totalAmount）;
}
}
/ * for（Planet p：plAdapter.getBox（））{
if（p.selected）{
result + =\\\
+ p.name ++ p.distance +€+q.tà：+p.getQuantità（）;
int quantitaInt = Integer.parseInt（p.getQuantità（））;
totalAmount + = p.distance * quantitaInt;
//a=String.valueOf(totalAmount）;
}
} * /
//Toast.makeText（getActivity（），result +\\\
+总金额：=+ totalAmount +€，Toast.LENGTH_LONG）.show（）;
Toast.makeText（getActivity（），result2 +\\\
+Total Amount：=+ totalAmount2 +€，Toast.LENGTH_LONG）.show
/ * Bundle bun2 = new Bundle（）;
bun2.putString（scelta，result）;
TwoFragment fgsearch2 = new TwoFragment（）;
fgsearch2.setArguments（bun2）;
android.support.v4.app.FragmentTransaction transaction2 = getActivity（）。getSupportFragmentManager（）。beginTransaction（）;
transaction2.replace（R.id.content_main，fgsearch2）;
transaction2.commit（）;
Bundle bun = new Bundle（）;
bun.putString（totale，a）;
TwoFragment fgsearch = new TwoFragment（）;
fgsearch.setArguments（bun）;
android.support.v4.app.FragmentTransaction transaction = getActivity（）。getSupportFragmentManager（）。beginTransaction（）;
transaction.replace（R.id.content_main2，fgsearch）;
transaction.commit（）; * /
}
}
第二个片段没有列表：
public class TwoFragment extends Fragment {
private View v;
Intent chooser = null;
public TwoFragment（）{
//必需的空公共构造函数
}
@Override
public void onCreate Bundle savedInstanceState）{
super.onCreate（savedInstanceState）;
}
@Override
public View onCreateView（LayoutInflater inflater，ViewGroup container，
Bundle savedInstanceState）{
//膨胀此片段的布局
查看rootView = inflater.inflate（R.layout.fragment_two，container，false）;
Button mButton =（Button）rootView.findViewById（R.id.newbutton）;
mButton.setOnClickListener（new View.OnClickListener（）{
public void onClick（View v）{
sendemail（）;
}
}）;
TextView titolo3 =（TextView）rootView.findViewById（R.id.result2）;
TextView titolo2 =（TextView）rootView.findViewById（R.id.quantità2）;
// TextView titolo =（TextView）rootView.findViewById（R.id.quantità3）;
Bundle bundle2 = getArguments（）;
if（bundle2！= null）{
String string = bundle2.getString（scelta2，null）;
titolo3.setText（string）;
}
Bundle bundle = getArguments（）;
if（bundle！= null）{
String myInt = bundle.getString（totale2，null）;
titolo2.setText（myInt）;
}
/ * Bundle bundle3 = getArguments（）;
if（bundle3！= null）{
String valuta = bundle3.getString（valuta，null）;
titolo.setText（valuta）;
} * /
return rootView;
}
public void sendemail（）{
Intent intent = new Intent（Intent.ACTION_SEND）;
intent.setData（Uri.parse（mailto：））;
String [] to = {marco_marcoletto@hotmail.it};
intent.putExtra（Intent.EXTRA_EMAIL，to）;
intent.putExtra（Intent.EXTRA_SUBJECT，ciao）;
intent.putExtra（Intent.EXTRA_TEXT，zao）;
intent.setType（message / rfc822）;
chooser = intent.createChooser（intent，manda email）;
startActivity（chooser）;
}
}
第三个片段带有CHECKBOX的列表：
public class ThreeFragment extends Fragment implements android.widget.CompoundButton.OnCheckedChangeListener {
ListView lv2;
ArrayList< Birra> birraList;
BirraAdapter biAdapter;
BirraAdapter.BirraHolder birraHolder;
BirraAdapter.BirraHolder holderr;
public ThreeFragment（）{
//必需的空公共构造函数
}
@Override
public View onCreateView（LayoutInflater inflater，ViewGroup container，
Bundle savedInstanceState）{
//为此片段扩充布局
ViewGroup rootView =（ViewGroup）inflater.inflate（R.layout.fragment_three，容器，假）;
Button mButton =（Button）rootView.findViewById（R.id.button2）;
mButton.setOnClickListener（new View.OnClickListener（）{
public void onClick（View v）{
showResult（v）;
} b $ b}）;
// return inflater.inflate（R.layout.fragment_list2，container，false）;
return rootView;
}
@Override
public void onViewCreated（View view，@Nullable Bundle savedInstanceState）{
super.onViewCreated（view，savedInstanceState）;
lv2 =（ListView）getView（）。findViewById（R.id.listview2）;
displayBirraList（）;
}
private void displayBirraList（）{
birraList = new ArrayList< Birra>（）;
birraList.add（new Birra（Paulaner，6，€））;
birraList.add（new Birra（Forst，7，€））;
birraList.add（new Birra（Peroni，5，€））;
birraList.add（new Birra（Corona，5，€））;
birraList.add（new Birra（Nastro Azzurro，4，€））;
biAdapter = new BirraAdapter（birraList，getContext（））{
@Override
public void onCheckedChanged（CompoundButton buttonView，boolean isChecked）{
int pos = lv2.getPositionForView（buttonView） ;
if（pos！= ListView.INVALID_POSITION）{
Birra b = birraList.get（pos）;
b.setSelected（isChecked）;
/*Toast.makeText（
getActivity（），
点击Pizza：+ p.getName（）+。State：is
+ isChecked，Toast.LENGTH_SHORT）.show（）; * /
}
}
};
lv2.setAdapter（biAdapter）;
}
/ * @Override
public void onPause（）{
//获取实例变量
SharedPreferences preferences = getContext ）.getSharedPreferences（MaterialTabs，android.content.Context.MODE_PRIVATE）;
boolean mCheckBoxValuee = preferences.getBoolean（CheckBox_Valuee，false）;
if（mCheckBoxValuee）{
holderr.chkBox_birra.setChecked（true）;
} else {
holderr.chkBox_birra.setChecked（false）;
}
super.onPause（）;
}
* /
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（），
点击Planet： + p.getName（）+。State：is
+ isChecked，Toast.LENGTH_SHORT）.show（）; * // ** // ** // ** // *
}
* /
}
public void showResult（View v）{
String result =Selected Product are：;
int totalAmount = 0;
String c =;
for（Birra b：biAdapter.getBox（））{
if（b.selected）{
result + =\\\
+ b。 name ++ b.distance +€+q.tà：+b.getQuantità（）;
int quantitaInt = Integer.parseInt（b.getQuantità（））;
totalAmount + = b.distance * quantitaInt;
c = String.valueOf（totalAmount）;
}
}
Toast.makeText（getActivity（），result +\\\
+总金额：=+ totalAmount +€ ，Toast.LENGTH_LONG）.show（）;
/ * Bundle bun2 = new Bundle（）;
bun2.putString（scelta2，result）;
TwoFragment fgsearch2 = new TwoFragment（）;
fgsearch2.setArguments（bun2）;
android.support.v4.app.FragmentTransaction transaction2 = getActivity（）。getSupportFragmentManager（）。beginTransaction（）;
transaction2.replace（R.id.content_main，fgsearch2）;
transaction2.commit（）;
Bundle bun = new Bundle（）;
bun.putString（totale2，c）;
TwoFragment fgsearch = new TwoFragment（）;
fgsearch.setArguments（bun）;
android.support.v4.app.FragmentTransaction transaction = getActivity（）。getSupportFragmentManager（）。beginTransaction（）;
transaction.replace（R.id.content_main2，fgsearch）;
transaction.commit（）; * /
}
}
LOGCAT：
05-10 12：34：17.975 20371-20371 / info.androidhive.materialtabs E / AndroidRuntime：FATAL EXCEPTION ：main
java.lang.NullPointerException
at info.androidhive.materialtabs.activity.MyListFragment.onPause（MyListFragment.java:103）
在android.support.v4.app.Fragment.performPause （Fragment.java:2139）
在android.support.v4.app.FragmentManagerImpl.moveToState（FragmentManager.java:1117）
在android.support.v4.app.FragmentManagerImpl.detachFragment（FragmentManager.java ：1408）
在android.support.v4.app.BackStackRecord.run（BackStackRecord.java:727）
在android.support.v4.app.FragmentManagerImpl.execPendingActions（FragmentManager.java:1617）
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions（FragmentManager.java:570）
在android.support.v4.app.FragmentPagerAdapter.finishUpdate（FragmentPagerAdapter.java:141）
在android.support.v4.view.ViewPager.populate（ViewPager.java:1025）
在android.support上android.support.v4.view.ViewPager.populate（ViewPager.java:1177）
。 v4.view.ViewPager $ 3.run（ViewPager.java:254）
在android.os.Handler.handleCallback（Handler.java:605）
在android.os.Handler.dispatchMessage（Handler.java ：92）
at android.os.Looper.loop（Looper.java:137）
在android.app.ActivityThread.main（ActivityThread.java:4424）
在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（本地方法）
解决方案 java.lang.NullPointerException 使用未初始化的组件。
这里，您的动机是setChecked / unChecked复选框到 PlanetAdapter code> onPause（）
回调。您可以这样做：
- 创建一个接口，用于将fragment与适配器通信。
- 在您的
onPause 回调发送命令到您的适配器以检查/取消选中您的复选框列表。
例如：
假设你的界面是这样的：
public interface AdapterCallback {
void onCheckboxCallback（boolean isChecked）;
}
在您的适配器实现 AdapterCallback 接口。然后你会得到 onCheckboxCallback（）方法。
@Override
public void onCheckboxCallback（boolean isChecked）{
//执行复选框检查/取消选中此处
}
在此方法中，您可以根据isChecked值检查/取消选中。
现在，在填充PlanetAdapter的Fragment / Activity中，方法
if（mCheckBoxValue）{
plAdapter.onCheckboxCallback（true）;
} else {
plAdapter.onCheckboxCallback（false）;
if i check a checkbox and go on tab without list view with checkbox and came to previous tab, i see checkbox checked previously...but if i click on another tab with list view with checkbox, my program crash...why?
now i post my code...
I hope that you can help me!
Thanks in advance!
ADAPTER CLASS:
public abstract class PlanetAdapter extends ArrayAdapter<Planet> implements CompoundButton.OnCheckedChangeListener{
private List<Planet> planetList;
private Context context;
ArrayList<Birra> objects;
public PlanetAdapter(List<Planet> planetList, Context context) {
super(context, R.layout.single_listview_item, planetList);
this.planetList = planetList;
this.context = context;
}
public class PlanetHolder {
public TextView planetName;
public TextView distView;
public TextView valuta;
public CheckBox chkBox;
public EditText edit;
public String quantità;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
View row = convertView;
PlanetHolder holder = null;
if (row == null) {
LayoutInflater inflater = ((Activity) context).getLayoutInflater();
row = inflater.inflate(R.layout.single_listview_item, parent, false);
holder = new PlanetHolder();
holder.planetName = (TextView) row.findViewById(R.id.name);
holder.distView = (TextView) row.findViewById(R.id.dist);
holder.valuta = (TextView) row.findViewById(R.id.valuta);
holder.chkBox = (CheckBox) row.findViewById(R.id.chk_box);
holder.edit = (EditText) row.findViewById(R.id.editText);
holder.edit.setVisibility(View.GONE);
holder.edit.setEnabled(false);
row.setTag(holder);
} else {
holder = (PlanetHolder) row.getTag();
}
final Planet p = planetList.get(position);
final PlanetHolder finalHolder = holder;
/* SharedPreferences preferences = getContext().getSharedPreferences("MaterialTabs", android.content.Context.MODE_PRIVATE);
boolean mCheckBoxValue = preferences .getBoolean("CheckBox_Value", false);
if (mCheckBoxValue) {
holder.chkBox.setChecked(true);
} else {
holder.chkBox.setChecked(false);
}*/
holder.chkBox.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (finalHolder.chkBox.isChecked()) {
finalHolder.edit.setVisibility(View.VISIBLE);
finalHolder.edit.setEnabled(true);
SharedPreferences preferences = getContext().getSharedPreferences("MaterialTabs", android.content.Context.MODE_PRIVATE);
/* SharedPreferences.Editor editor = preferences.edit();
editor.putBoolean("showActivity", finalHolder.chkBox.isChecked());
editor.commit();*/
// boolean value= true;
SharedPreferences.Editor mEditor = preferences.edit();
mEditor.putBoolean("CheckBox_Value", finalHolder.chkBox.isChecked());
mEditor.commit();
finalHolder.edit.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
@Override
public void afterTextChanged(Editable s) {
p.setQuantità(finalHolder.edit.getText().toString().trim());
/* SharedPreferences preferences = getContext().getSharedPreferences("PROJECT_NAME", android.content.Context.MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("KEY", finalHolder.edit.getText().toString().trim());
editor.commit();*/
}
});
} else {
finalHolder.edit.setVisibility(View.GONE);
finalHolder.edit.setEnabled(false);
finalHolder.edit.setText(null);
}
}
});
holder.planetName.setText(p.getName());
holder.distView.setText("" + p.getDistance());
holder.valuta.setText("" + p.getValuta());
holder.chkBox.setChecked(p.isSelected());
holder.chkBox.setTag(p);
holder.edit.setEnabled(false);
return row;
}
ArrayList<Planet> getBox() {
ArrayList<Planet> box = new ArrayList<Planet>();
for (Planet p : planetList) {
if (p.selected)
box.add(p);
}
return box;
}
}
FIRST FRAGMENT CLASS WITH LISTVIEW WITH CHECKBOX:
public class MyListFragment extends Fragment implements android.widget.CompoundButton.OnCheckedChangeListener {
ListView lv;
ArrayList<Planet> planetList;
PlanetAdapter plAdapter;
BirraAdapter biAdapter;
PlanetAdapter.PlanetHolder holder;
@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);
}
@Override
public void onPause() {
//get the instance variables
SharedPreferences preferences = getContext().getSharedPreferences("MaterialTabs", android.content.Context.MODE_PRIVATE);
boolean mCheckBoxValue = preferences.getBoolean("CheckBox_Value", false);
if (mCheckBoxValue) {
holder.chkBox.setChecked(true);
} else {
holder.chkBox.setChecked(false);
}
super.onPause();
}
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 result2 = "Selected Product are :";
int totalAmount2 = 0;
String a = "";
for (Birra b : biAdapter.getBox()) {
if (b.selected) {
result2 += "\n" + b.name + " " + b.distance + "€" + "q.tà :" + b.getQuantità();
int quantitaInt = Integer.parseInt(b.getQuantità());
totalAmount2 += b.distance * quantitaInt;
//a=String.valueOf(totalAmount);
}
}
/* 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;
//a=String.valueOf(totalAmount);
}
}*/
//Toast.makeText(getActivity(), result + "\n" + "Total Amount:=" + totalAmount + "€", Toast.LENGTH_LONG).show();
Toast.makeText(getActivity(), result2 + "\n" + "Total Amount:=" + totalAmount2 + "€", Toast.LENGTH_LONG).show();
/*Bundle bun2 = new Bundle();
bun2.putString("scelta", result);
TwoFragment fgsearch2 = new TwoFragment();
fgsearch2.setArguments(bun2);
android.support.v4.app.FragmentTransaction transaction2 = getActivity().getSupportFragmentManager().beginTransaction();
transaction2.replace(R.id.content_main, fgsearch2);
transaction2.commit();
Bundle bun = new Bundle();
bun.putString("totale", a);
TwoFragment fgsearch = new TwoFragment();
fgsearch.setArguments(bun);
android.support.v4.app.FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.content_main2, fgsearch);
transaction.commit();*/
}
}
SECOND FRAGMENT WITHOUT LISTVIEW:
public class TwoFragment extends Fragment {
private View v;
Intent chooser = null;
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);
Button mButton = (Button) rootView.findViewById(R.id.newbutton);
mButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
sendemail();
}
});
TextView titolo3 = (TextView) rootView.findViewById(R.id.result2);
TextView titolo2 = (TextView) rootView.findViewById(R.id.quantità2);
//TextView titolo = (TextView)rootView.findViewById(R.id.quantità3);
Bundle bundle2 = getArguments();
if (bundle2 != null) {
String string = bundle2.getString("scelta2", null);
titolo3.setText(string);
}
Bundle bundle = getArguments();
if (bundle != null) {
String myInt = bundle.getString("totale2", null);
titolo2.setText(myInt);
}
/* Bundle bundle3=getArguments();
if(bundle3 != null){
String valuta=bundle3.getString("valuta", null);
titolo.setText(valuta);
}*/
return rootView;
}
public void sendemail() {
Intent intent = new Intent(Intent.ACTION_SEND);
intent.setData(Uri.parse("mailto:"));
String[] to = {"marco_marcoletto@hotmail.it"};
intent.putExtra(Intent.EXTRA_EMAIL, to);
intent.putExtra(Intent.EXTRA_SUBJECT, "ciao");
intent.putExtra(Intent.EXTRA_TEXT, "zao");
intent.setType("message/rfc822");
chooser = intent.createChooser(intent, "manda email");
startActivity(chooser);
}
}
THIRD FRAGMENT WITH LISTVIEW WITH CHECKBOX:
public class ThreeFragment extends Fragment implements android.widget.CompoundButton.OnCheckedChangeListener {
ListView lv2;
ArrayList<Birra> birraList;
BirraAdapter biAdapter;
BirraAdapter.BirraHolder birraHolder;
BirraAdapter.BirraHolder holderr;
public ThreeFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.fragment_three, container, false);
Button mButton = (Button) rootView.findViewById(R.id.button2);
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);
lv2 = (ListView) getView().findViewById(R.id.listview2);
displayBirraList();
}
private void displayBirraList() {
birraList = new ArrayList<Birra>();
birraList.add(new Birra("Paulaner", 6, "€"));
birraList.add(new Birra("Forst", 7, "€"));
birraList.add(new Birra("Peroni", 5, "€"));
birraList.add(new Birra("Corona", 5, "€"));
birraList.add(new Birra("Nastro Azzurro", 4, "€"));
biAdapter = new BirraAdapter(birraList, getContext()) {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
int pos = lv2.getPositionForView(buttonView);
if (pos != ListView.INVALID_POSITION) {
Birra b = birraList.get(pos);
b.setSelected(isChecked);
/*Toast.makeText(
getActivity(),
"Clicked on Pizza: " + p.getName() + ". State: is "
+ isChecked, Toast.LENGTH_SHORT).show();*/
}
}
};
lv2.setAdapter(biAdapter);
}
/* @Override
public void onPause() {
//get the instance variables
SharedPreferences preferences = getContext().getSharedPreferences("MaterialTabs", android.content.Context.MODE_PRIVATE);
boolean mCheckBoxValuee = preferences.getBoolean("CheckBox_Valuee", false);
if (mCheckBoxValuee) {
holderr.chkBox_birra.setChecked(true);
} else {
holderr.chkBox_birra.setChecked(false);
}
super.onPause();
}
*/
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 c = "";
for (Birra b : biAdapter.getBox()) {
if (b.selected) {
result += "\n" + b.name + " " + b.distance + "€" + "q.tà :" + b.getQuantità();
int quantitaInt = Integer.parseInt(b.getQuantità());
totalAmount += b.distance * quantitaInt;
c = String.valueOf(totalAmount);
}
}
Toast.makeText(getActivity(), result + "\n" + "Total Amount:=" + totalAmount + "€", Toast.LENGTH_LONG).show();
/* Bundle bun2 = new Bundle();
bun2.putString("scelta2", result);
TwoFragment fgsearch2 = new TwoFragment();
fgsearch2.setArguments(bun2);
android.support.v4.app.FragmentTransaction transaction2 = getActivity().getSupportFragmentManager().beginTransaction();
transaction2.replace(R.id.content_main, fgsearch2);
transaction2.commit();
Bundle bun = new Bundle();
bun.putString("totale2", c);
TwoFragment fgsearch = new TwoFragment();
fgsearch.setArguments(bun);
android.support.v4.app.FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.content_main2, fgsearch);
transaction.commit();*/
}
}
LOGCAT:
05-10 12:34:17.975 20371-20371/info.androidhive.materialtabs E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.NullPointerException
at info.androidhive.materialtabs.activity.MyListFragment.onPause(MyListFragment.java:103)
at android.support.v4.app.Fragment.performPause(Fragment.java:2139)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1117)
at android.support.v4.app.FragmentManagerImpl.detachFragment(FragmentManager.java:1408)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:727)
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$3.run(ViewPager.java:254)
at android.os.Handler.handleCallback(Handler.java:605)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4424)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
at dalvik.system.NativeStart.main(Native Method)
解决方案 java.lang.NullPointerException means you are trying to use a component that is not initialized.
here, your motive is setChecked/unChecked of checkbox into PlanetAdapter from onPause() callback. You can do in this way:
- Create an Interface that will communicate between fragment to your adapter.
- In your
onPause callback send command to your adapter for check/uncheck of your checkbox list.
Example:
Suppose your interface is like it:
public interface AdapterCallback {
void onCheckboxCallback(boolean isChecked);
}
In your Adapter implements AdapterCallback Interface. Then you will get onCheckboxCallback() method.
@Override
public void onCheckboxCallback(boolean isChecked) {
// Do your checkbox check/uncheck here
}
In this method you can checked/unchecked based on your isChecked value.
Now, in your Fragment/Activity that populating PlanetAdapter, just call this method
if (mCheckBoxValue) {
plAdapter.onCheckboxCallback(true);
} else {
plAdapter.onCheckboxCallback(false);
这篇关于共享首选项和onPause不工作的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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