我不知道为什么变量public class MainActivity extends Activity {
@Override
public void onResume() {
super.onResume();
if(getIntent().getStringExtra("timestamp")!=null){
Toast.makeText(getApplicationContext(),"Has Timestamp",Toast.LENGTH_SHORT).show();
}
}
在我的代码中的某些地方为空。
在这些行中没关系，因此变量不为null：
myInt当我在myInt = bundle2.getString("scelta2", null);
titolo3.setText(myInt);
中使用变量myInt时，它为空。
可能是什么问题？
先谢谢大家！
TwoFragment.java
Paragraph p1=new Paragraph(myInt); ThreeFragment.java
从我通过变量的碎片：
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={"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);
}*/
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);
}
}
主要是致电三个片段：
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();
}
}
答案 0 :(得分：0)
bundle.getString（String key，String defaultValue）中的文档说：
返回与给定键关联的值，如果给定键不存在所需类型的映射，或者如果空值与给定键显式关联，则返回defaultValue。
* @param key a String, or null
* @param defaultValue Value to return if key does not exist or if a null
* value is associated with the given key.
* @return the String value associated with the given key, or defaultValue
* if no valid String object is currently mapped to that key.
所以，问题是在你的情况下，捆绑包没有那个密钥。
你可以试试这个：
Bundle bun2 = new Bundle();
bun2.putString("scelta2", result);
TwoFragment fgsearch2 = new TwoFragment();
if(fgsearch2 .getArguments() != null){
fgsearch2 .getArguments().clear();
fgsearch2 .getArguments().putAll(bun2);
}else{
fgsearch2 .setArguments(bun2);
}
android.support.v4.app.FragmentTransaction transaction2=getActivity().getSupportFragmentManager().beginTransaction();
transaction2.replace(R.id.content_main, fgsearch2);
transaction2.commit();
答案 1 :(得分：0)
你可以开发你的应用程序，如：
从你的活动中调用片段我创建了像
这样的方法addFragment(new Fragment1().setArguments("String values"));
addFramgent方法如下：
public void addFragment(Fragment fragment) {
FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
fragmentTransaction.add(R.id.mainfragment, fragment).addToBackStack(fragment.toString()).commit();
}
您将在片段中获取字符串值，例如：
class Fragment1 extends Fragment{
String value;
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_user, container, false);
Log.e("","Value:"+value);
return view;
}
public Fragment setArguments(String value) {
this.value = value;
return this;
}
}