当我尝试从片段中打开timepicker或datepicker时，我收到此错误。我知道这是一个背景问题，但我不知道如何解决它。
05-11 13:56:12.026 18397-18397/com.victor.martin.agenda.app E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.ClassCastException: com.victor.martin.agenda.app.AgendaActivity cannot be cast to com.victor.martin.agenda.app.TimePickerFragment$TimePickerFragmentListener
at com.victor.martin.agenda.app.TimePickerFragment.onTimeSet(TimePickerFragment.java:39)
at android.app.TimePickerDialog.tryNotifyTimeSet(TimePickerDialog.java)
at android.app.TimePickerDialog.onClick(TimePickerDialog.java)
at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java)
at android.os.Handler.dispatchMessage(Handler.java)
at android.os.Looper.loop(Looper.java)
at android.app.ActivityThread.main(ActivityThread.java)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java)
at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:133)
at dalvik.system.NativeStart.main(Native Method)
消息来源
AgendaActivity.java ＆lt; - Main
package com.victor.martin.agenda.app;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import com.victor.martin.agenda.app.fragments.HistoryFragment;
import com.victor.martin.agenda.app.fragments.NewEventFragment;
import java.util.Locale;
public class AgendaActivity extends ActionBarActivity implements ActionBar.TabListener {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_agenda);
// Set up the action bar.
final ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
// When swiping between different sections, select the corresponding
// tab. We can also use ActionBar.Tab#select() to do this if we have
// a reference to the Tab.
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by
// the adapter. Also specify this Activity object, which implements
// the TabListener interface, as the callback (listener) for when
// this tab is selected.
actionBar.addTab(
actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.agenda, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
switch(position) {
case 0: return HistoryFragment.newInstance("History" + position + 1);
case 1: return NewEventFragment.newInstance("New Event" + position + 1);
default: return HistoryFragment.newInstance("History, Default" + position + 1);
}
}
@Override
public int getCount() {
// Show 2 total pages.
return 2;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.str_history).toUpperCase(l);
case 1:
return getString(R.string.str_new_event).toUpperCase(l);
//case 2:
// return getString(R.string.title_section3).toUpperCase(l);
}
return null;
}
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_agenda, container, false);
return rootView;
}
}
}
NewEventFragment.java
package com.victor.martin.agenda.app.fragments;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import com.victor.martin.agenda.app.DatePickerFragment;
import com.victor.martin.agenda.app.R;
import com.victor.martin.agenda.app.TimePickerFragment;
/**
* Created by McFly on 11/05/2014.
*/
public class NewEventFragment extends Fragment implements TimePickerFragment.TimePickerFragmentListener,DatePickerFragment.DatePickerFragmentListener {
Button bt_date, bt_time, bt_clear, bt_save;
EditText et_description, et_location;
Context _c;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_new_event, container, false);
_c = getActivity();
bt_date = (Button)v.findViewById(R.id.bt_date);
bt_time = (Button)v.findViewById(R.id.bt_date);
bt_clear = (Button)v.findViewById(R.id.bt_clear);
bt_save = (Button)v.findViewById(R.id.bt_save);
et_description = (EditText)v.findViewById(R.id.et_description);
et_location = (EditText)v.findViewById(R.id.et_location);
bt_date.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
showDatePickerDialog();
}
});
bt_time.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
showTimePickerDialog();
}
});
return v;
}
public static NewEventFragment newInstance(String text) {
NewEventFragment f = new NewEventFragment();
Bundle b = new Bundle();
b.putString("msg", text);
f.setArguments(b);
return f;
}
// Methods
//Llamado cuando el usuario pulsa el botón de TimePicker
public void showTimePickerDialog() {
TimePickerFragment newFragment = new TimePickerFragment();
newFragment.show(this.getFragmentManager(), "timePicker");
}
//Llamado cuando el usuario pulsa el botón de DatePicker
public void showDatePickerDialog() {
DatePickerFragment newFragment = new DatePickerFragment();
newFragment.show(this.getFragmentManager(), "datePicker");
}
//Llamado cuando el usuario acaba la selección y los datos son enviados a la actividad
@Override
public void onFinishTimePickerDialog(int hourOfDay, int minute) {
// TODO Auto-generated method stub
//Toast.makeText(this, "Hora: " + hourOfDay + minute, Toast.LENGTH_SHORT).show();
bt_time.setText(hourOfDay + ":" + minute);
}
//Llamado cuando el usuario acaba la selección y los datos son enviados a la actividad
@Override
public void onFinishDatePickerDialog(int year, int month, int day) {
// TODO Auto-generated method stub
//Toast.makeText(this, "Fecha: " + year + month + day, Toast.LENGTH_SHORT).show();
bt_date.setText(day + "/" + month + "/" + year);
}
}
TimePickerFragment.java
package com.victor.martin.agenda.app;
import android.app.Dialog;
import android.app.TimePickerDialog;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.text.format.DateFormat;
import android.widget.TimePicker;
import java.util.Calendar;
/**
* Created by McFly on 10/05/2014.
*/
public class TimePickerFragment extends DialogFragment implements TimePickerDialog.OnTimeSetListener {
//Interface creada para implementar un método que podamos utilizar como
//enlace de la actividad en curso y le enviemos la información
//seleccionada por el usuario.
public interface TimePickerFragmentListener{
void onFinishTimePickerDialog(int hourOfDay, int minute);
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
//Datos que seleccionara el usuario.
final Calendar c = Calendar.getInstance();
int hour = c.get(Calendar.HOUR_OF_DAY);
int minute = c.get(Calendar.MINUTE);
// Creamos la insntacia del TimePicke para devolverla.
return new TimePickerDialog(getActivity(), this, hour, minute, DateFormat.is24HourFormat(getActivity()));
}
public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
// Do something with the time chosen by the user
TimePickerFragmentListener activity = (TimePickerFragmentListener) getActivity();
activity.onFinishTimePickerDialog(hourOfDay, minute);
}
}
答案 0 :(得分：1)
TimePickerFragmentListener activity = (TimePickerFragmentListener) getActivity();
问题是您的Activity没有实现TimePickerFragmentListener。您可以在NewEventFragment中实现它，这样您也可以这样开始对话：
public void showTimePickerDialog() {
TimePickerFragment newFragment = new TimePickerFragment();
// added request code also
newFragment.setTargetFragment(this, 0);
newFragment.show(this.getFragmentManager(), "timePicker");
}
并使用getTargetFragment：
访问父片段TimePickerFragmentListener listener = (TimePickerFragmentListener) getTargetFragment();
答案 1 :(得分：0)
Kupsef的回答解决了这个问题。