我似乎在将 Activity 中获得的数据传递给 Fragment 时遇到问题。数据没有出现在 listfragment 中！这是我的列表片段活动。每次我将一个项目添加到列表中时，我都会重新实例化该片段，也就是捆绑一个项目并使用新片段中的构造函数来执行它。
package com.example.sample;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.widget.Toast;
import com.actionbarsherlock.app.ActionBar;
import com.actionbarsherlock.app.ActionBar.Tab;
import com.actionbarsherlock.app.SherlockFragmentActivity;
import com.actionbarsherlock.view.Menu;
import com.actionbarsherlock.view.MenuItem;
/**
* An activity representing a list of Courses. This activity has different
* presentations for handset and tablet-size devices. On handsets, the activity
* presents a list of items, which when touched, lead to a
* {@link CourseDetailActivity} representing item details. On tablets, the
* activity presents the list of items and item details side-by-side using two
* vertical panes.
* <p>
* The activity makes heavy use of fragments. The list of items is a
* {@link CourseListFragment} and the item details (if present) is a
* {@link CourseDetailFragment}.
* <p>
* This activity also implements the required
* {@link CourseListFragment.Callbacks} interface to listen for item selections.
*/
public class CourseListActivity extends SherlockFragmentActivity implements
CourseListFragment.Callbacks {
CourseListFragment listFrag;
public static String courseName;
private static final int REQUEST_CODE = 10;
/**
* Whether or not the activity is in two-pane mode, i.e. running on a tablet
* device.
*/
private boolean mTwoPane;
private boolean once = true;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_course_list);
if (findViewById(R.id.course_detail_container) != null) {
// The detail container view will be present only in the
// large-screen layouts (res/values-large and
// res/values-sw600dp). If this view is present, then the
// activity should be in two-pane mode.
mTwoPane = true;
// In two-pane mode, list items should be given the
// 'activated' state when touched.
listFrag = ((CourseListFragment) getSupportFragmentManager().findFragmentById(
R.id.course_list));
listFrag.setActivateOnItemClick(true);
}
// TODO: If exposing deep links into your app, handle intents here.
}
/**
* Callback method from {@link CourseListFragment.Callbacks} indicating that
* the item with the given ID was selected.
*/
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getSupportMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
public boolean onOptionsItemSelected(MenuItem item) {
boolean bool;
switch (item.getItemId()) {
case R.id.add_course:
Intent intent = new Intent(this, CourseAddActivity.class);
startActivityForResult(intent, REQUEST_CODE);
bool = true;
default:
bool = super.onOptionsItemSelected(item);
}
return bool;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == RESULT_OK && requestCode == REQUEST_CODE) {
if (data.hasExtra("courseName")) {
courseName = data.getExtras().getString("courseName");
Bundle args = new Bundle();
args.putString("courseKey", courseName);
listFrag = new CourseListFragment(args);
}
}
}
@Override
public void onItemSelected(String id) {
if (mTwoPane) {
// In two-pane mode, show the detail view in this activity by
// adding or replacing the detail fragment using a
// fragment transaction.
if (once) {
ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// initiating both tabs and set text to it.
ActionBar.Tab assignTab = actionBar.newTab().setText(
"Assignments");
ActionBar.Tab schedTab = actionBar.newTab().setText("Schedule");
ActionBar.Tab contactTab = actionBar.newTab()
.setText("Contact");
// Create three fragments to display content
Fragment assignFragment = new Assignments();
Fragment schedFragment = new Schedule();
Fragment contactFragment = new Contact();
assignTab.setTabListener(new MyTabsListener(assignFragment));
schedTab.setTabListener(new MyTabsListener(schedFragment));
contactTab.setTabListener(new MyTabsListener(contactFragment));
actionBar.addTab(assignTab);
actionBar.addTab(schedTab);
actionBar.addTab(contactTab);
once = false;
}
} else {
// In single-pane mode, simply start the detail activity
// for the selected item ID.
Intent detailIntent = new Intent(this, CourseDetailActivity.class);
startActivity(detailIntent);
}
}
class MyTabsListener implements ActionBar.TabListener {
public Fragment fragment;
public MyTabsListener(Fragment fragment) {
this.fragment = fragment;
}
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
ft.replace(R.id.course_detail_container, fragment);
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
ft.remove(fragment);
}
}
}
这是我的 ListFragment，我在其中创建了两个构造函数，一个接受参数。
package com.example.sample;
import java.util.ArrayList;
import android.app.Activity;
import android.os.Build;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import com.actionbarsherlock.app.SherlockListFragment;
/**
* A list fragment representing a list of Courses. This fragment also supports
* tablet devices by allowing list items to be given an 'activated' state upon
* selection. This helps indicate which item is currently being viewed in a
* {@link CourseDetailFragment}.
* <p>
* Activities containing this fragment MUST implement the {@link Callbacks}
* interface.
*/
public class CourseListFragment extends SherlockListFragment {
private static String courseName;
ArrayList<String> courseItems;
ArrayAdapter<String> adapter;
/**
* The serialization (saved instance state) Bundle key representing the
* activated item position. Only used on tablets.
*/
private static final String STATE_ACTIVATED_POSITION = "activated_position";
/**
* The fragment's current callback object, which is notified of list item
* clicks.
*/
private Callbacks mCallbacks = sDummyCallbacks;
/**
* The current activated item position. Only used on tablets.
*/
private int mActivatedPosition = ListView.INVALID_POSITION;
/**
* A callback interface that all activities containing this fragment must
* implement. This mechanism allows activities to be notified of item
* selections.
*/
public interface Callbacks {
/**
* Callback for when an item has been selected.
*/
public void onItemSelected(String id);
}
/**
* A dummy implementation of the {@link Callbacks} interface that does
* nothing. Used only when this fragment is not attached to an activity.
*/
private static Callbacks sDummyCallbacks = new Callbacks() {
@Override
public void onItemSelected(String id) {
}
};
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public CourseListFragment() {
}
public CourseListFragment(Bundle args) {
courseName = args.get("courseKey").toString();
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
courseItems = new ArrayList<String>();
adapter = new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, courseItems);
// TODO: replace with a real list adapter.
int layout = (Build.VERSION.SDK_INT >= 11) ? android.R.layout.simple_list_item_activated_1
: android.R.layout.simple_list_item_1;
setListAdapter(adapter);
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// Restore the previously serialized activated item position.
if (savedInstanceState != null
&& savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) {
setActivatedPosition(savedInstanceState
.getInt(STATE_ACTIVATED_POSITION));
courseItems.add(courseName);
adapter.notifyDataSetChanged();
}
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// Activities containing this fragment must implement its callbacks.
if (!(activity instanceof Callbacks)) {
throw new IllegalStateException(
"Activity must implement fragment's callbacks.");
}
mCallbacks = (Callbacks) activity;
}
@Override
public void onDetach() {
super.onDetach();
// Reset the active callbacks interface to the dummy implementation.
mCallbacks = sDummyCallbacks;
}
@Override
public void onListItemClick(ListView listView, View view, int position,
long id) {
super.onListItemClick(listView, view, position, id);
// Notify the active callbacks interface (the activity, if the
// fragment is attached to one) that an item has been selected.
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
if (mActivatedPosition != ListView.INVALID_POSITION) {
// Serialize and persist the activated item position.
outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition);
}
}
/**
* Turns on activate-on-click mode. When this mode is on, list items will be
* given the 'activated' state when touched.
*/
public void setActivateOnItemClick(boolean activateOnItemClick) {
// When setting CHOICE_MODE_SINGLE, ListView will automatically
// give items the 'activated' state when touched.
getListView().setChoiceMode(
activateOnItemClick ? ListView.CHOICE_MODE_SINGLE
: ListView.CHOICE_MODE_NONE);
}
private void setActivatedPosition(int position) {
if (position == ListView.INVALID_POSITION) {
getListView().setItemChecked(mActivatedPosition, false);
} else {
getListView().setItemChecked(position, true);
}
mActivatedPosition = position;
}
}
任何帮助都非常感谢！谢谢你！