我遇到了一些困难
片段类
public class FragmentFour extends Fragment {
ImageView ivIcon;
TextView tvItemName;
public static final String IMAGE_RESOURCE_ID = "iconResourceID";
public static final String ITEM_NAME = "itemName";
ListView exerciseList;
ExerciseAdapter exercise_ArrayAdapter;
ExerciseDatabase exerciseDatabase, db;
Cursor C;
String eID, eTitle, eLength, eDate, eTime;
String APPTAG = "Exercise Tracker ExpenseHistory: ";
Integer exerciseID_int;
ArrayList exerciseID_Array, exerciseTitle_Array, exerciseLength_Array, exerciseDate_Array, exerciseTime_Array;
public FragmentFour()
{
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_exercise, container, false);
initializeVariables(view);
//SET CUSTOM ADAPTER FOR LISTVIEW
exerciseList.setAdapter(exercise_ArrayAdapter);
registerForContextMenu(exerciseList);
// READING A DB
ExerciseDatabase exerciseDatabase = new ExerciseDatabase(getActivity());
SQLiteDatabase readableDB = exerciseDatabase.getReadableDatabase();
C = readableDB.query("ExerciseTable", new String[] { "_ID", "EXERCISE", "DURATION", "DATE", "TIME"},
null, null, null, null, "DATE ASC");
if (C == null || !C.moveToFirst())
{
view = inflater.inflate(R.layout.empty_view, null);
}
else
{
do
{
String exerciseID_String = "";
String exerciseTitle_String = "";
String exerciseLength_String = "";
String exerciseDate_String = "";
String exerciseTime_String = "";
// Get the data from the database
exerciseID_int = C.getInt(C.getColumnIndex("_ID"));
eTitle = C.getString(C.getColumnIndex("EXERCISE"));
eLength = C.getString(C.getColumnIndex("DURATION"));
eDate = C.getString(C.getColumnIndex("DATE"));
eTime = C.getString(C.getColumnIndex("TIME"));
eID = exerciseID_int.toString();
//Build strings of each record to then be set to the listview
exerciseID_String = eID;
exerciseTitle_String = eTitle;
exerciseLength_String = eLength;
exerciseDate_String = eDate;
exerciseTime_String = eTime;
//Add the new strings to the corresponding array
exerciseID_Array.add(exerciseID_String);
exerciseTitle_Array.add(exerciseTitle_String);
exerciseLength_Array.add(exerciseLength_String);
exerciseDate_Array.add(exerciseDate_String);
exerciseTime_Array.add(exerciseTime_String);
}
while (C.moveToNext());
}
// Close cursor and database to avoid memory leaks
C.close();
readableDB.close();
// Tell adapter there is new data so update the listview accordingly
exercise_ArrayAdapter.notifyDataSetChanged();
return view;
}
// Initalizes the variables used in the activity
public void initializeVariables(View v) {
exerciseList = (ListView) v.findViewById(R.id.exerciseHistory_listview);
exerciseID_Array = new ArrayList();
exerciseTitle_Array = new ArrayList();
exerciseLength_Array = new ArrayList();
exerciseDate_Array = new ArrayList();
exerciseTime_Array = new ArrayList();
exercise_ArrayAdapter = new ExerciseAdapter(this, R.layout.exercise_item_row, exerciseID_Array, exerciseTitle_Array,
exerciseLength_Array, exerciseDate_Array, exerciseTime_Array);
}
// Create a menu
public boolean onCreateOptionsMenu(android.view.Menu menu) {
getMenuInflater().inflate(R.menu.history_menu, menu);
return true;
}
// If the add icon is selected, the ExerciseEntry activity appears, allowing the user to add data to the database
public boolean onOptionsItemSelected(MenuItem item)
{
switch(item.getItemId())
{
case R.id.ic_add:
Intent openExerciseEntry = new Intent(this, ExerciseEntry.class);
startActivity(openExerciseEntry);
finish();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}
活动类
public class ExpenseHistory extends Activity {
ListView expenseList;
CustomAdapter expense_ArrayAdapter;
ExpenseDatabase eDatabase;
Cursor C;
String eID, eTitle, eAmount, eDate, eTime;
String APPTAG = "Expense Tracker ExpenseHistory: ";
Integer expenseID_int;
ArrayList expenseID_Array, expenseTitle_Array, expenseAmount_Array, expenseDate_Array, expenseTime_Array;
ExpenseDatabase db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Set the layout to the activity_expense_history layout file
setContentView(R.layout.activity_expense_history);
// Initalize the variables used in this activity
initializeVariables();
// Record in the logcat when the application is Created
Log.v(APPTAG, "onCreate() called");
//SET CUSTOM ADAPTER FOR LISTVIEW
expenseList.setAdapter(expense_ArrayAdapter);
expenseList.setEmptyView(findViewById(R.id.empty));
registerForContextMenu(expenseList);
// READING A DB
SQLiteDatabase readableDB = eDatabase.getReadableDatabase();
C = readableDB.query("ExpenseTable", new String[] { "_ID", "EXPENSETITLE", "AMOUNT", "EXPENSEDATE", "EXPENSETIME"},
null, null, null, null, "EXPENSEDATE ASC");
if (C == null || !C.moveToFirst())
{
}
else
{
do
{
String expenseID_String = "";
String expenseTitle_String = "";
String expenseAmount_String = "";
String expenseDate_String = "";
String expenseTime_String = "";
// Get the data from the database
expenseID_int = C.getInt(C.getColumnIndex("_ID"));
eTitle = C.getString(C.getColumnIndex("EXPENSETITLE"));
eAmount = C.getString(C.getColumnIndex("AMOUNT"));
eDate = C.getString(C.getColumnIndex("EXPENSEDATE"));
eTime = C.getString(C.getColumnIndex("EXPENSETIME"));
eID = expenseID_int.toString();
//Build strings of each record to then be set to the listview
expenseID_String = eID;
expenseTitle_String = eTitle;
expenseAmount_String = eAmount;
expenseDate_String = eDate;
expenseTime_String = eTime;
//Add the new strings to the corresponding array
expenseID_Array.add(expenseID_String);
expenseTitle_Array.add(expenseTitle_String);
expenseAmount_Array.add(expenseAmount_String);
expenseDate_Array.add(expenseDate_String);
expenseTime_Array.add(expenseTime_String);
}
while (C.moveToNext());
}
// Close cursor and database to avoid memory leaks
C.close();
readableDB.close();
// Tell adapter there is new data so update the listview accordingly
expense_ArrayAdapter.notifyDataSetChanged();
}
// Initalizes the variables used in the activity
private void initializeVariables() {
expenseList = (ListView) findViewById(R.id.expenseHistory_listview);
eDatabase = new ExpenseDatabase(this);
expenseID_Array = new ArrayList();
expenseTitle_Array = new ArrayList();
expenseAmount_Array = new ArrayList();
expenseDate_Array = new ArrayList();
expenseTime_Array = new ArrayList();
expense_ArrayAdapter = new CustomAdapter(this, R.layout.item_row, expenseID_Array, expenseTitle_Array,
expenseAmount_Array, expenseDate_Array, expenseTime_Array);
}
// Creates a context menu for the ExpenseHistory class which allows a pop up box to appear when something happens
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.expense_context, menu);
}
// When an item is selected, an options box appears
@Override
public boolean onContextItemSelected(MenuItem item) {
AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
int position = info.position;
switch (item.getItemId()) {
case R.id.delete:
{
String temp = expenseTitle_Array.get(position).toString();
expenseID_Array.remove(position);
expenseTitle_Array.remove(position);
expenseAmount_Array.remove(position);
expenseDate_Array.remove(position);
expenseTime_Array.remove(position);
db = new ExpenseDatabase(this);
SQLiteDatabase readableDB = db.getWritableDatabase();
readableDB.delete("ExpenseTable", "EXPENSETITLE=?",
new String[]{temp});
expense_ArrayAdapter.notifyDataSetChanged();
}
return true;
default:
return super.onContextItemSelected(item);
}
}
// Create a menu
public boolean onCreateOptionsMenu(android.view.Menu menu) {
getMenuInflater().inflate(R.menu.history_menu, menu);
return true;
}
// If the back icon is selected, the user is returned to the MainActivity
public boolean onOptionsItemSelected(MenuItem item)
{
switch(item.getItemId())
{
case R.id.ic_back:
Intent openMainActivity = new Intent(this, MainActivity.class);
startActivity(openMainActivity);
finish();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
感谢任何帮助。
答案 0 :(得分：1)
我发现当我学习修改活动以使用片段时，在很多情况下，添加“getActivitiy（）。[与在activty中相同的代码]将是一个很好的第一件事，如果那样没有用，很多时候Eclipse都会建议修复。
答案 1 :(得分：0)
对于选项菜单，您需要覆盖片段中的onCreate()并致电setHasOptionsMenu()。