我不知道为什么变量
myInt在这些行中是可以的，所以变量不为空：
myInt = bundle2.getString("scelta2", null);
titolo3.setText(myInt);
当我在
myIntParagraph p1=new Paragraph(myInt);可能是什么问题？
TwoFragment.java
public class TwoFragment extends Fragment{
private View v;
Intent chooser=null;
String myInt="";
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();
createPDF();
viewPDF();
}
});
TextView titolo3 = (TextView)rootView.findViewById(R.id.result);
TextView titolo2 = (TextView)rootView.findViewById(R.id.result2);
TextView titolo4 = (TextView)rootView.findViewById(R.id.resultpizze);
//TextView titolo = (TextView)rootView.findViewById(R.id.quantità3);
/* Bundle bundle2=getArguments();
if(bundle2 != null){
String string = bundle2.getString("scelta2", null);
titolo3.setText(string);
}*/
Bundle bundle2=getArguments();
if(bundle2 != null){
myInt = bundle2.getString("scelta2", null);
titolo3.setText(myInt);
}
Bundle bundle3=getArguments();
if(bundle3 != null){
// String myInt3 = bundle3.getString("totalebirre", null);
// cazzo2=Integer.parseInt(myInt3);
int cazzo2=bundle3.getInt("totalebirre");
titolo2.setText(String.valueOf(cazzo2));
}
Bundle bundle=getArguments();
if(bundle != null){
// String myInt2 = bundle2.getString("totalepizze", null);
// cazzo=Integer.parseInt(myInt2);
//titolo2.setText(myInt2);
String string=bundle.getString("scelta3", null);
titolo4.setText(string);
}
return rootView;
}
/* public void sendemail(){
Intent intent = new Intent(Intent.ACTION_SEND);
intent.setData(Uri.parse("mailto:"));
String[] to={"[email protected]"};
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);
}*/
public void createPDF() {
Document doc = new Document();
try {
String path = Environment.getExternalStorageDirectory()
.getAbsolutePath() + "/droidText";
File dir = new File(path);
if (!dir.exists())
dir.mkdirs();
Log.d("PDFCreator", "PDF Path: " + path);
File file = new File(dir, "sample.pdf");
FileOutputStream fOut = new FileOutputStream(file);
PdfWriter.getInstance(doc, fOut);
// open the document
doc.open();
ByteArrayOutputStream stream = new ByteArrayOutputStream();
Bitmap bitmap = BitmapFactory.decodeResource(getContext()
.getResources(), R.drawable.androtuto);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
Image myImg = Image.getInstance(stream.toByteArray());
myImg.setAlignment(Image.MIDDLE);
// add image to document
doc.add(myImg);
Paragraph p1 = new Paragraph(myInt);
Log.d("ciao",myInt);
Font paraFont = new Font(Font.COURIER);
p1.setAlignment(Paragraph.ALIGN_CENTER);
p1.setFont(paraFont);
// add paragraph to document
doc.add(p1);
Paragraph p2 = new Paragraph("Ciao");
Font paraFont2 = new Font(Font.COURIER, 14.0f, Color.GREEN);
p2.setAlignment(Paragraph.ALIGN_CENTER);
p2.setFont(paraFont2);
doc.add(p2);
stream = new ByteArrayOutputStream();
bitmap = BitmapFactory.decodeResource(getContext()
.getResources(), R.drawable.android);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
myImg = Image.getInstance(stream.toByteArray());
myImg.setAlignment(Image.MIDDLE);
// add image to document
doc.add(myImg);
// set footer
Phrase footerText = new Phrase("Pied de page ");
HeaderFooter pdfFooter = new HeaderFooter(footerText, false);
doc.setFooter(pdfFooter);
} catch (DocumentException de) {
Log.e("PDFCreator", "DocumentException:" + de);
} catch (IOException e) {
Log.e("PDFCreator", "ioException:" + e);
} finally {
doc.close();
}
}
public void viewPDF(){
String path = "/sdcard/droidText/sample.pdf";
File targetFile = new File(path);
Uri targetUri = Uri.fromFile(targetFile);
Intent intent;
intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(targetUri, "application/pdf");
startActivity(intent);
}
}
ThreeFragment.java
（我传递变量的片段）
public class ThreeFragment extends Fragment implements
android.widget.CompoundButton.OnCheckedChangeListener {
ListView lv2;
ArrayList<Planet> planetList;
ListView lv;
ArrayList<Birra> birraList;
BirraAdapter biAdapter;
PlanetAdapter plAdapter;
Planet p;
String myInt="";
PlanetAdapter.PlanetHolder holder;
public ThreeFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
final 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) {
MyListFragment mlf=new MyListFragment();
mlf.showResult(v);
// MyListFragment.showResult(v);
showResult2(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);
}
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 showResult2(View v) {
String result = "Selected Product are :";
int totalAmount = 0;
// String a = "";
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;
// a=String.valueOf(totalAmount);
}
}
/* for (Planet p : plAdapter.getBox()) {
if (p.isSelected()) {
result += "\n" + p.getName() + " " + p.getDistance() + "€" + "q.tà :" + p.getQuantità();
int quantitaInt = Integer.parseInt(p.getQuantità());
//totalAmount2+=p.distance * quantitaInt;
//z=String.valueOf(totalAmount2);
}
}*/
Toast.makeText(getActivity(), result + "\n" +myInt + "\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("totalebirre", a);
bun.putInt("totalebirre", totalAmount);
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();
}
}
调用三个片段的主函数：
public class MainBirra extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mainbirra);
getSupportFragmentManager().beginTransaction().
replace(R.id.fragmentContainer2, new ThreeFragment()).commit();
}
/* @Override protected void onDestroy() {
SharedPreferences preferences=getSharedPreferences("states", Context.MODE_PRIVATE);
SharedPreferences.Editor editor=preferences.edit();
editor.clear().apply();
super.onDestroy();
Log.e("OnDestroy", " callback_2");
}*/
}
在我看来，你可以创建一个静态方法来返回你想要启动的片段的实例，在这个方法中你将初始化你的变量，比如TwoFragment中的myInt。 所以在 TwoFragment.java 中添加这个方法
public static TwoFragment getInstance(String myInt){
TwoFragment twoFragment=new TwoFragment();
twoFragment.myInt=myInt;
return twoFragment;
}
当您需要在其他地方启动片段时，请使用此代码代替默认构造函数
public class ThreeFragment extends Fragment implements
android.widget.CompoundButton.OnCheckedChangeListener {
ListView lv2;
ArrayList<Planet> planetList;
ListView lv;
ArrayList<Birra> birraList;
BirraAdapter biAdapter;
PlanetAdapter plAdapter;
Planet p;
String myInt="";
PlanetAdapter.PlanetHolder holder;
public ThreeFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
final 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) {
MyListFragment mlf=new MyListFragment();
mlf.showResult(v);
// MyListFragment.showResult(v);
showResult2(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);
}
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 showResult2(View v) {
String result = "Selected Product are :";
int totalAmount = 0;
// String a = "";
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;
// a=String.valueOf(totalAmount);
}
}
/* for (Planet p : plAdapter.getBox()) {
if (p.isSelected()) {
result += "\n" + p.getName() + " " + p.getDistance() + "€" + "q.tà :" + p.getQuantità();
int quantitaInt = Integer.parseInt(p.getQuantità());
//totalAmount2+=p.distance * quantitaInt;
//z=String.valueOf(totalAmount2);
}
}*/
Toast.makeText(getActivity(), result + "\n" +myInt + "\n" + "Total Amount:=" + totalAmount + "€", Toast.LENGTH_LONG).show();
TwoFragment fgsearch2=TwoFragment.getInstance(result);
fgsearch2.setArguments(bun2);
android.support.v4.app.FragmentTransaction transaction2 = getActivity().getSupportFragmentManager().beginTransaction();
transaction2.replace(R.id.content_main, fgsearch2);
transaction2.commit();
}
}
public class TwoFragment extends Fragment {
private View v;
String myInt="";
int cazzo2;
String scelta3;
public TwoFragment() {
// Required empty public constructor
}
public static TwoFragment getInstance(String myInt,int cazzo2,String scelta3){
TwoFragment twoFragment=new TwoFragment();
twoFragment.myInt=myInt;
twoFragment.cazzo2=cazzo2;
twoFragment.scelta3=scelta3;
return twoFragment;
}
@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();
createPDF();
viewPDF();
}
});
TextView titolo3 = (TextView)rootView.findViewById(R.id.result);
TextView titolo2 = (TextView)rootView.findViewById(R.id.result2);
TextView titolo4 = (TextView)rootView.findViewById(R.id.resultpizze);
titolo3.setText(myInt);
titolo2.setText(String.valueOf(cazzo2));
titolo4.setText(scelta3);
return rootView;
}
/* public void sendemail(){
Intent intent = new Intent(Intent.ACTION_SEND);
intent.setData(Uri.parse("mailto:"));
String[] to={"[email protected]"};
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);
}*/
public void createPDF() {
Document doc = new Document();
try {
String path = Environment.getExternalStorageDirectory()
.getAbsolutePath() + "/droidText";
File dir = new File(path);
if (!dir.exists())
dir.mkdirs();
Log.d("PDFCreator", "PDF Path: " + path);
File file = new File(dir, "sample.pdf");
FileOutputStream fOut = new FileOutputStream(file);
PdfWriter.getInstance(doc, fOut);
// open the document
doc.open();
ByteArrayOutputStream stream = new ByteArrayOutputStream();
Bitmap bitmap = BitmapFactory.decodeResource(getContext()
.getResources(), R.drawable.androtuto);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
Image myImg = Image.getInstance(stream.toByteArray());
myImg.setAlignment(Image.MIDDLE);
// add image to document
doc.add(myImg);
Paragraph p1 = new Paragraph(myInt);
Log.d("ciao",myInt);
Font paraFont = new Font(Font.COURIER);
p1.setAlignment(Paragraph.ALIGN_CENTER);
p1.setFont(paraFont);
// add paragraph to document
doc.add(p1);
Paragraph p2 = new Paragraph("Ciao");
Font paraFont2 = new Font(Font.COURIER, 14.0f, Color.GREEN);
p2.setAlignment(Paragraph.ALIGN_CENTER);
p2.setFont(paraFont2);
doc.add(p2);
stream = new ByteArrayOutputStream();
bitmap = BitmapFactory.decodeResource(getContext()
.getResources(), R.drawable.android);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
myImg = Image.getInstance(stream.toByteArray());
myImg.setAlignment(Image.MIDDLE);
// add image to document
doc.add(myImg);
// set footer
Phrase footerText = new Phrase("Pied de page ");
HeaderFooter pdfFooter = new HeaderFooter(footerText, false);
doc.setFooter(pdfFooter);
} catch (DocumentException de) {
Log.e("PDFCreator", "DocumentException:" + de);
} catch (IOException e) {
Log.e("PDFCreator", "ioException:" + e);
} finally {
doc.close();
}
}
public void viewPDF(){
String path = "/sdcard/droidText/sample.pdf";
File targetFile = new File(path);
Uri targetUri = Uri.fromFile(targetFile);
Intent intent;
intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(targetUri, "application/pdf");
startActivity(intent);
}
}
和其他片段
public class ThreeFragment extends Fragment implements
android.widget.CompoundButton.OnCheckedChangeListener {
ListView lv2;
ArrayList<Planet> planetList;
ListView lv;
ArrayList<Birra> birraList;
BirraAdapter biAdapter;
PlanetAdapter plAdapter;
Planet p;
String myInt="";
PlanetAdapter.PlanetHolder holder;
public ThreeFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
final 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) {
MyListFragment mlf=new MyListFragment();
mlf.showResult(v);
// MyListFragment.showResult(v);
showResult2(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);
}
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 showResult2(View v) {
String result = "Selected Product are :";
int totalAmount = 0;
// String a = "";
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;
// a=String.valueOf(totalAmount);
}
}
/* for (Planet p : plAdapter.getBox()) {
if (p.isSelected()) {
result += "\n" + p.getName() + " " + p.getDistance() + "€" + "q.tà :" + p.getQuantità();
int quantitaInt = Integer.parseInt(p.getQuantità());
//totalAmount2+=p.distance * quantitaInt;
//z=String.valueOf(totalAmount2);
}
}*/
Toast.makeText(getActivity(), result + "\n" +myInt + "\n" + "Total Amount:=" + totalAmount + "€", Toast.LENGTH_LONG).show();
TwoFragment fgsearch2 = TwoFragment.getInstance(result,totalAmount,"test");
android.support.v4.app.FragmentTransaction transaction2 = getActivity().getSupportFragmentManager().beginTransaction();
transaction2.replace(R.id.content_main, fgsearch2);
transaction2.commit();
}
}