我正在开设一门课程，我真的到了这样的地步，我认为我不是真的适合这个工作领域（开发），应该坚持图形设计。至少我想完成这个课程，但我不断收到我不明白的错误！根据{{1}}，以下行存在问题
logcattitleView.setText(toDoItem.getTitle());
package course.labs.todomanager;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.text.ParseException;
import java.util.Date;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ListView;
import android.widget.TextView;
import course.labs.todomanager.ToDoItem.Priority;
import course.labs.todomanager.ToDoItem.Status;
public class ToDoManagerActivity extends ListActivity {
private static final int ADD_TODO_ITEM_REQUEST = 0;
private static final String FILE_NAME = "TodoManagerActivityData.txt";
private static final String TAG = "Lab-UserInterface";
// IDs for menu items
private static final int MENU_DELETE = Menu.FIRST;
private static final int MENU_DUMP = Menu.FIRST + 1;
ToDoListAdapter mAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Create a new TodoListAdapter for this ListActivity's ListView
mAdapter = new ToDoListAdapter(getApplicationContext());
// Put divider between ToDoItems and FooterView
getListView().setFooterDividersEnabled(true);
// TODO - Inflate footerView for footer_view.xml file
//TextView footerView = (TextView) findViewById(R.id.footerView);
//LayoutInflater inflitrate= getLayoutInflater();
//inflitrate.inflate(R.id.footerView, getListView());
TextView footerView = (TextView) getLayoutInflater().inflate(R.layout.footer_view, null);
// NOTE: You can remove this block once you've implemented the assignment
//if (null == footerView) {
// return;
//}
// TODO - Add footerView to ListView
ListView viewer= getListView();
viewer.addFooterView(footerView);
footerView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Log.i(TAG,"Entered footerView.OnClickListener.onClick()");
//TODO - Implement OnClick().
Intent addone= new Intent (ToDoManagerActivity.this, AddToDoActivity.class);
startActivityForResult(addone, ADD_TODO_ITEM_REQUEST);
}
});
// TODO - Attach the adapter to this ListActivity's ListView
viewer.setAdapter(mAdapter);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
Log.i(TAG,"Entered onActivityResult()");
// TODO - Check result code and request code
// if user submitted a new ToDoItem
// Create a new ToDoItem from the data Intent
// and then add it to the adapter
if (requestCode == ADD_TODO_ITEM_REQUEST && resultCode == RESULT_OK)
{
ToDoItem toDoItem = new ToDoItem(data);
mAdapter.add(toDoItem);
}
}
// Do not modify below here
@Override
public void onResume() {
super.onResume();
// Load saved ToDoItems, if necessary
if (mAdapter.getCount() == 0)
loadItems();
}
@Override
protected void onPause() {
super.onPause();
// Save ToDoItems
saveItems();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
menu.add(Menu.NONE, MENU_DELETE, Menu.NONE, "Delete all");
menu.add(Menu.NONE, MENU_DUMP, Menu.NONE, "Dump to log");
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case MENU_DELETE:
mAdapter.clear();
return true;
case MENU_DUMP:
dump();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
private void dump() {
for (int i = 0; i < mAdapter.getCount(); i++) {
String data = ((ToDoItem) mAdapter.getItem(i)).toLog();
Log.i(TAG, "Item " + i + ": " + data.replace(ToDoItem.ITEM_SEP, ","));
}
}
// Load stored ToDoItems
private void loadItems() {
BufferedReader reader = null;
try {
FileInputStream fis = openFileInput(FILE_NAME);
reader = new BufferedReader(new InputStreamReader(fis));
String title = null;
String priority = null;
String status = null;
Date date = null;
while (null != (title = reader.readLine())) {
priority = reader.readLine();
status = reader.readLine();
date = ToDoItem.FORMAT.parse(reader.readLine());
mAdapter.add(new ToDoItem(title, Priority.valueOf(priority),
Status.valueOf(status), date));
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
} finally {
if (null != reader) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
// Save ToDoItems to file
private void saveItems() {
PrintWriter writer = null;
try {
FileOutputStream fos = openFileOutput(FILE_NAME, MODE_PRIVATE);
writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
fos)));
for (int idx = 0; idx < mAdapter.getCount(); idx++) {
writer.println(mAdapter.getItem(idx));
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (null != writer) {
writer.close();
}
}
}
}
package course.labs.todomanager;
import java.util.Calendar;
import java.util.Date;
import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.app.TimePickerDialog;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.TimePicker;
import course.labs.todomanager.ToDoItem.Priority;
import course.labs.todomanager.ToDoItem.Status;
public class AddToDoActivity extends Activity {
// 7 days in milliseconds - 7 * 24 * 60 * 60 * 1000
private static final int SEVEN_DAYS = 604800000;
private static final String TAG = "Lab-UserInterface";
private static String timeString;
private static String dateString;
private static TextView dateView;
private static TextView timeView;
private Date mDate;
private RadioGroup mPriorityRadioGroup;
private RadioGroup mStatusRadioGroup;
private EditText mTitleText;
private RadioButton mDefaultStatusButton;
private RadioButton mDefaultPriorityButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_todo);
mTitleText = (EditText) findViewById(R.id.title);
mDefaultStatusButton = (RadioButton) findViewById(R.id.statusNotDone);
mDefaultPriorityButton = (RadioButton) findViewById(R.id.medPriority);
mPriorityRadioGroup = (RadioGroup) findViewById(R.id.priorityGroup);
mStatusRadioGroup = (RadioGroup) findViewById(R.id.statusGroup);
dateView = (TextView) findViewById(R.id.date);
timeView = (TextView) findViewById(R.id.time);
// Set the default date and time
setDefaultDateTime();
// OnClickListener for the Date button, calls showDatePickerDialog() to
// show
// the Date dialog
final Button datePickerButton = (Button) findViewById(R.id.date_picker_button);
datePickerButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
showDatePickerDialog();
}
});
// OnClickListener for the Time button, calls showTimePickerDialog() to
// show the Time Dialog
final Button timePickerButton = (Button) findViewById(R.id.time_picker_button);
timePickerButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
showTimePickerDialog();
}
});
// OnClickListener for the Cancel Button,
final Button cancelButton = (Button) findViewById(R.id.cancelButton);
cancelButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Log.i(TAG, "Entered cancelButton.OnClickListener.onClick()");
// TODO - Indicate result and finish
Intent returnIntent = new Intent();
setResult(RESULT_CANCELED,returnIntent);
finish();
}
});
// TODO - Set up OnClickListener for the Reset Button
final Button resetButton = (Button) findViewById(R.id.resetButton);
resetButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Log.i(TAG, "Entered resetButton.OnClickListener.onClick()");
// TODO - Reset data to default values
mTitleText.setText("");
setDefaultDateTime();
mDefaultStatusButton.setChecked(true);
mDefaultPriorityButton.setChecked(true);
}
});
// Set up OnClickListener for the Submit Button
final Button submitButton = (Button) findViewById(R.id.submitButton);
submitButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Log.i(TAG, "Entered submitButton.OnClickListener.onClick()");
// gather ToDoItem data
// TODO - Get the current Priority
Priority priority = getPriority();
// TODO - Get the current Status
Status status = getStatus();
// TODO - Get the current ToDoItem Title
String titleString = getToDoTitle();
// Construct the Date string
String fullDate = dateString + " " + timeString;
// Package ToDoItem data into an Intent
Intent data = new Intent();
ToDoItem.packageIntent(data, titleString, priority, status,
fullDate);
// TODO - return data Intent and finish
setResult(Activity.RESULT_OK,data);
finish();
}
});
}
// Do not modify below this point.
private void setDefaultDateTime() {
// Default is current time + 7 days
mDate = new Date();
mDate = new Date(mDate.getTime() + SEVEN_DAYS);
Calendar c = Calendar.getInstance();
c.setTime(mDate);
setDateString(c.get(Calendar.YEAR), c.get(Calendar.MONTH),
c.get(Calendar.DAY_OF_MONTH));
dateView.setText(dateString);
setTimeString(c.get(Calendar.HOUR_OF_DAY), c.get(Calendar.MINUTE),
c.get(Calendar.MILLISECOND));
timeView.setText(timeString);
}
private static void setDateString(int year, int monthOfYear, int dayOfMonth) {
// Increment monthOfYear for Calendar/Date -> Time Format setting
monthOfYear++;
String mon = "" + monthOfYear;
String day = "" + dayOfMonth;
if (monthOfYear < 10)
mon = "0" + monthOfYear;
if (dayOfMonth < 10)
day = "0" + dayOfMonth;
dateString = year + "-" + mon + "-" + day;
}
private static void setTimeString(int hourOfDay, int minute, int mili) {
String hour = "" + hourOfDay;
String min = "" + minute;
if (hourOfDay < 10)
hour = "0" + hourOfDay;
if (minute < 10)
min = "0" + minute;
timeString = hour + ":" + min + ":00";
}
private Priority getPriority() {
switch (mPriorityRadioGroup.getCheckedRadioButtonId()) {
case R.id.lowPriority: {
return Priority.LOW;
}
case R.id.highPriority: {
return Priority.HIGH;
}
default: {
return Priority.MED;
}
}
}
private Status getStatus() {
switch (mStatusRadioGroup.getCheckedRadioButtonId()) {
case R.id.statusDone: {
return Status.DONE;
}
default: {
return Status.NOTDONE;
}
}
}
private String getToDoTitle() {
return mTitleText.getText().toString();
}
// DialogFragment used to pick a ToDoItem deadline date
public static class DatePickerFragment extends DialogFragment implements
DatePickerDialog.OnDateSetListener {
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the current date as the default date in the picker
final Calendar c = Calendar.getInstance();
int year = c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH);
int day = c.get(Calendar.DAY_OF_MONTH);
// Create a new instance of DatePickerDialog and return it
return new DatePickerDialog(getActivity(), this, year, month, day);
}
@Override
public void onDateSet(DatePicker view, int year, int monthOfYear,
int dayOfMonth) {
setDateString(year, monthOfYear, dayOfMonth);
dateView.setText(dateString);
}
}
// DialogFragment used to pick a ToDoItem deadline time
public static class TimePickerFragment extends DialogFragment implements
TimePickerDialog.OnTimeSetListener {
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the current time as the default values for the picker
final Calendar c = Calendar.getInstance();
int hour = c.get(Calendar.HOUR_OF_DAY);
int minute = c.get(Calendar.MINUTE);
// Create a new instance of TimePickerDialog and return
return new TimePickerDialog(getActivity(), this, hour, minute, true);
}
public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
setTimeString(hourOfDay, minute, 0);
timeView.setText(timeString);
}
}
private void showDatePickerDialog() {
DialogFragment newFragment = new DatePickerFragment();
newFragment.show(getFragmentManager(), "datePicker");
}
private void showTimePickerDialog() {
DialogFragment newFragment = new TimePickerFragment();
newFragment.show(getFragmentManager(), "timePicker");
}
}
package course.labs.todomanager;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import android.content.Intent;
public class ToDoItem {
public static final String ITEM_SEP = System.getProperty("line.separator");
public enum Priority {
LOW, MED, HIGH
};
public enum Status {
NOTDONE, DONE
};
public final static String TITLE = "title";
public final static String PRIORITY = "priority";
public final static String STATUS = "status";
public final static String DATE = "date";
public final static String FILENAME = "filename";
public final static SimpleDateFormat FORMAT = new SimpleDateFormat(
"yyyy-MM-dd HH:mm:ss", Locale.US);
private String mTitle = new String();
private Priority mPriority = Priority.LOW;
private Status mStatus = Status.NOTDONE;
private Date mDate = new Date();
ToDoItem(String title, Priority priority, Status status, Date date) {
this.mTitle = title;
this.mPriority = priority;
this.mStatus = status;
this.mDate = date;
}
// Create a new ToDoItem from data packaged in an Intent
ToDoItem(Intent intent) {
mTitle = intent.getStringExtra(ToDoItem.TITLE);
mPriority = Priority.valueOf(intent.getStringExtra(ToDoItem.PRIORITY));
mStatus = Status.valueOf(intent.getStringExtra(ToDoItem.STATUS));
try {
mDate = ToDoItem.FORMAT.parse(intent.getStringExtra(ToDoItem.DATE));
} catch (ParseException e) {
mDate = new Date();
}
}
public String getTitle() {
return mTitle;
}
public void setTitle(String title) {
mTitle = title;
}
public Priority getPriority() {
return mPriority;
}
public void setPriority(Priority priority) {
mPriority = priority;
}
public Status getStatus() {
return mStatus;
}
public void setStatus(Status status) {
mStatus = status;
}
public Date getDate() {
return mDate;
}
public void setDate(Date date) {
mDate = date;
}
// Take a set of String data values and
// package them for transport in an Intent
public static void packageIntent(Intent intent, String title,
Priority priority, Status status, String date) {
intent.putExtra(ToDoItem.TITLE, title);
intent.putExtra(ToDoItem.PRIORITY, priority.toString());
intent.putExtra(ToDoItem.STATUS, status.toString());
intent.putExtra(ToDoItem.DATE, date);
}
public String toString() {
return mTitle + ITEM_SEP + mPriority + ITEM_SEP + mStatus + ITEM_SEP
+ FORMAT.format(mDate);
}
public String toLog() {
return "Title:" + mTitle + ITEM_SEP + "Priority:" + mPriority
+ ITEM_SEP + "Status:" + mStatus + ITEM_SEP + "Date:"
+ FORMAT.format(mDate);
}
}
02-06 13：11：20.711：E / AndroidRuntime（1288）：致命异常：主要 02-06 13：11：20.711：E / AndroidRuntime（1288）：java.lang.NullPointerException 02-06 13：11：20.711：E / AndroidRuntime（1288）：at＆gt; course.labs.todomanager.ToDoListAdapter.getView（ToDoListAdapter.java:105） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.widget.HeaderViewListAdapter.getView（HeaderViewListAdapter.java:220） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.widget.AbsListView.obtainView（AbsListView.java:2177） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.widget.ListView.makeAndAddView（ListView.java:1840） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.widget.ListView.fillSpecific（ListView.java:1321） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.widget.ListView.layoutChildren（ListView.java:1633） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.widget.AbsListView.onLayout（AbsListView.java:2012） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.View.layout（View.java:14289） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.ViewGroup.layout（ViewGroup.java:4562） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.widget.FrameLayout.onLayout（FrameLayout.java:448） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.View.layout（View.java:14289） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.ViewGroup.layout（ViewGroup.java:4562） 02-06 13：11：20.711：E / AndroidRuntime（1288）：at com.android.internal.widget.ActionBarOverlayLayout.onLayout（ActionBarOverlayLayout.java:349） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.View.layout（View.java:14289） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.ViewGroup.layout（ViewGroup.java:4562） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.widget.FrameLayout.onLayout（FrameLayout.java:448） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.View.layout（View.java:14289） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.ViewGroup.layout（ViewGroup.java:4562） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.ViewRootImpl.performLayout（ViewRootImpl.java:1976） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.ViewRootImpl.performTraversals（ViewRootImpl.java:1730） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.ViewRootImpl.doTraversal（ViewRootImpl.java:1004） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.ViewRootImpl $ TraversalRunnable.run（ViewRootImpl.java:5481） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.Choreographer $ CallbackRecord.run（Choreographer.java:749） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.Choreographer.doCallbacks（Choreographer.java:562） 02-06 13：11：20.711：E / AndroidRuntime（1288）：在android.view.Choreographer.doFrame（Choreographer.java:532） 02-06 13：11：20.711：E / AndroidRuntime（1288）：at＆gt; android.view.Choreographer $ FrameDisplayEventReceiver.run（Choreographer.java:735） 02-06 13：11：20.711：E / AndroidRuntime（1288）：at＆gt; android.os.Handler.handleCallback（Handler.java:730） 02-06 13：11：20.711：E / AndroidRuntime（1288）：at＆gt; android.os.Handler.dispatchMessage（Handler.java:92） 02-06 13：11：20.711：E / AndroidRuntime（1288）：at＆gt; android.os.Looper.loop（Looper.java:137） 02-06 13：11：20.711：E / AndroidRuntime（1288）：at＆gt; android.app.ActivityThread.main（ActivityThread.java:5103） 02-06 13：11：20.711：E / AndroidRuntime（1288）：at＆gt; java.lang.reflect.Method.invokeNative（Native Method） 02-06 13：11：20.711：E / AndroidRuntime（1288）：at java.lang.reflect.Method.invoke（Method.java:525） 02-06 13：11：20.711：E / AndroidRuntime（1288）：at＆gt; com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:737） 02-06 13：11：20.711：E / AndroidRuntime（1288）：at＆gt; com.android.internal.os.ZygoteInit.main（ZygoteInit.java:553） 02-06 13：11：20.711：E / AndroidRuntime（1288）：at＆gt; dalvik.system.NativeStart.main（Native Method） 02-06 13：11：26.121：I / Process（1288）：发送信号。 PID：1288 SIG：9
感谢您提前提供的任何帮助！
答案 0 :(得分：1)
请确保您的titleView（带有id：priorityView）位于您为R.layout.add_todo充气的布局中
如果情况不是这样，你应该把它放在那里。如果这没有帮助，请发布您的布局xml文件。
答案 1 :(得分：0)
我不知道您是否找到了解决方案，但您可以尝试切换以下内容
convertView=inflator.inflate(R.layout.add_todo, null);
到
convertView=inflator.inflate(R.layout.add_todo, parent);