FragmentHost 有ViewPager，并且viewpager 的片段需要来自FragmentHost 的数据来创建它们的视图。
如何获取数据。数据是自定义类。
一种方法是使用自定义类的Serializable 实现。但我想避免这种情况，因为该类包含其他自定义类的数组和 Map。
同时还可以有多个FragmentHost 实例处于活动状态，每个活动一个FragmentHost。
【问题讨论】：
标签： android android-fragments communication greenrobot-eventbus
看看这个进行交流
public class CrimePagerActivity extends AppCompatActivity {
private static final String EXTRA_CRIME_ID = "com.android.ankitt.criminalintent.activities.extra.crime.id";
private ViewPager mViewPager;
private List<Crime> mCrimes;
public static Intent newIntent(Context packageContext, UUID crimeId) {
Intent intent = new Intent(packageContext, CrimePagerActivity.class);
intent.putExtra(EXTRA_CRIME_ID, crimeId);
return intent;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_crime_pager);
UUID crimeId = (UUID) getIntent().getSerializableExtra(EXTRA_CRIME_ID);
mViewPager = (ViewPager) findViewById(R.id.actvity_crime_pager_view_pager);
mCrimes = CrimeLab.get(this).getCrimes();
FragmentManager manager = getSupportFragmentManager();
mViewPager.setAdapter(new FragmentPagerAdapter(manager) {
@Override
public Fragment getItem(int position) {
Crime crime = mCrimes.get(position);
return CrimeFragment.newInstance(crime.getId());
}
@Override
public int getCount() {
return mCrimes.size();
}
});
for (int i = 0; i < mCrimes.size(); i++) {
if (mCrimes.get(i).getId().equals(crimeId)) {
mViewPager.setCurrentItem(i);
break;
}
}
}
}
片段
public static CrimeFragment newInstance(UUID crimeId) {
Bundle args = new Bundle();
args.putSerializable(ARG_CRIME_ID, crimeId);
CrimeFragment fragment = new CrimeFragment();
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
/*mCrime = new Crime();*/
/*UUID crimeId = (UUID)getActivity().getIntent().getSerializableExtra(CrimeActivity.EXTRA_CRIME_ID);*/
UUID crimeId = (UUID) getArguments().getSerializable(ARG_CRIME_ID);
mCrime = CrimeLab.get(getActivity()).getCrime(crimeId);
mFilePhoto = CrimeLab.get(getActivity()).getPhotoFile(mCrime);
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_crime, container, false);
mEditText = (EditText) view.findViewById(R.id.crime_title);
mEditText.setText(mCrime.getTitile()); //Updating Crime fragment with crime
mEditText.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) {
mCrime.setTitile(toString());
}
@Override
public void afterTextChanged(Editable s) {
}
});
final Intent pickContact = new Intent(Intent.ACTION_PICK, ContactsContract.Contacts.CONTENT_URI);
/*pickContact.addCategory(Intent.CATEGORY_HOME);*/
mSuspectButton = (Button) view.findViewById(R.id.crime_suspect);
mSuspectButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivityForResult(pickContact, REQUEST_CONTACT);
}
});
mReportButton = (Button) view.findViewById(R.id.crime_report);
mReportButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(Intent.ACTION_SEND);
intent.setType("text/plain");
intent.putExtra(Intent.EXTRA_TEXT, getCrimeReport());
intent.putExtra(Intent.EXTRA_SUBJECT, getString(R.string.crime_report_subject));
intent = Intent.createChooser(intent, getString(R.string.send_report));
startActivity(intent);
}
});
mDateButton = (Button) view.findViewById(R.id.crime_date);
updateDate((mCrime.getDate()).toString());
/*mDateButton.setEnabled(false);*/
/* Design a date picker for an application */
mDateButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
FragmentManager fragmentManager = getFragmentManager();
/*DatePickerFragment dialog = new DatePickerFragment();*/
DatePickerFragment dialog = DatePickerFragment.newInstance(mCrime.getDate());
dialog.setTargetFragment(CrimeFragment.this, REQUEST_DATE);
dialog.show(fragmentManager, DIALOG_DATE);
}
});
mCheckBox = (CheckBox) view.findViewById(R.id.crime_solved);
mCheckBox.setChecked(mCrime.isSolved()); //Updating Crime fragment with crime
mCheckBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
mCrime.setSolved(isChecked);
}
});
if (mCrime.getSuspect() != null) {
mSuspectButton.setText(mCrime.getSuspect());
}
PackageManager packageManager = getActivity().getPackageManager();
if (packageManager.resolveActivity(pickContact, PackageManager.MATCH_DEFAULT_ONLY) == null) {
mSuspectButton.setEnabled(false);
}
mImageButton = (ImageButton) view.findViewById(R.id.crime_camera);
final Intent captureImage = new Intent(MediaStore.ACTION_IMAGE_CAPTURE) ;
boolean canTakePhoto = mFilePhoto != null &&
captureImage.resolveActivity(packageManager)!=null;
mImageButton.setEnabled(canTakePhoto);
if (canTakePhoto){
Uri uri = Uri.fromFile(mFilePhoto);
captureImage.putExtra(MediaStore.EXTRA_OUTPUT,uri);
}
mImageButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivityForResult(captureImage,REQUEST_PHOTO);
}
});
mImageView = (ImageView) view.findViewById(R.id.crime_photo);
updatePhotoView();
return view;
}
public void returnResult() {
getActivity().setResult(Activity.RESULT_OK, null);
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode != Activity.RESULT_OK) {
return;
}
if (requestCode == REQUEST_DATE) {
Date date = (Date) data
.getSerializableExtra(DatePickerFragment.EXTRA_DATE);
mCrime.setDate(date);
updateDate(mCrime.getDate().toString());
} else if (requestCode == REQUEST_CONTACT && data != null) {
Uri contactUri = data.getData();
String[] queryFields = new String[]{
ContactsContract.Contacts.DISPLAY_NAME
};
Cursor cursor = getActivity().getContentResolver().query(contactUri, queryFields, null, null, null);
try {
if (cursor.getCount() == 0) {
return;
}
cursor.moveToFirst();
String suspect = cursor.getString(0);
mCrime.setSuspect(suspect);
mSuspectButton.setText(suspect);
} finally {
cursor.close();
}
}else if (requestCode == REQUEST_PHOTO){
updatePhotoView();
}
}
private void updateDate(String text) {
mDateButton.setText(text);
}
private String getCrimeReport() {
String solvedString = null;
if (mCrime.isSolved()) {
solvedString = getString(R.string.crime_report_solved);
} else {
solvedString = getString(R.string.crime_report_unsolved);
}
String dateFormat = "EEE, MM dd";
String dateString = DateFormat.format(dateFormat, mCrime.getDate()).toString();
String suspect = mCrime.getSuspect();
if (suspect == null) {
suspect = getString(R.string.crime_report_no_suspect);
} else {
suspect = getString(R.string.crime_report_suspect, suspect);
}
String report = getString(R.string.crime_report, mCrime.getTitile(), dateString, solvedString, suspect);
return report;
}
@Override
public void onPause() {
super.onPause();
CrimeLab.get(getActivity()).updateCrime(mCrime);
}
private void updatePhotoView() {
if (mFilePhoto == null || !mFilePhoto.exists()) {
mImageView.setImageDrawable(null);
} else {
Bitmap bitmap = PictureUtils.getScaledBitmap(
mFilePhoto.getPath(), getActivity());
mImageView.setImageBitmap(bitmap);
}
}
}
【讨论】：