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在我的应用程序中，当我按下主页按钮时，我的应用程序崩溃了。这是 LogCat 有人可以帮我解决这个问题吗？

 08-22 14:28:36.078: E/AndroidRuntime(509): FATAL EXCEPTION: main
    08-22 14:28:36.078: E/AndroidRuntime(509): java.lang.RuntimeException: Unable to pause activity {com.example.girtsreminder/com.example.girtsreminder.ReminderEditActivity}: java.lang.NullPointerException
    08-22 14:28:36.078: E/AndroidRuntime(509):  at android.app.ActivityThread.performPauseActivity(ActivityThread.java:3348)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at android.app.ActivityThread.performPauseActivity(ActivityThread.java:3305)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at android.app.ActivityThread.handlePauseActivity(ActivityThread.java:3288)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at android.app.ActivityThread.access$2500(ActivityThread.java:125)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2040)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at android.os.Handler.dispatchMessage(Handler.java:99)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at android.os.Looper.loop(Looper.java:123)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at android.app.ActivityThread.main(ActivityThread.java:4627)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at java.lang.reflect.Method.invokeNative(Native Method)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at java.lang.reflect.Method.invoke(Method.java:521)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at dalvik.system.NativeStart.main(Native Method)
    08-22 14:28:36.078: E/AndroidRuntime(509): Caused by: java.lang.NullPointerException
    08-22 14:28:36.078: E/AndroidRuntime(509):  at com.example.girtsreminder.ReminderEditActivity.onSaveInstanceState(ReminderEditActivity.java:273)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at android.app.Activity.performSaveInstanceState(Activity.java:1036)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at android.app.Instrumentation.callActivityOnSaveInstanceState(Instrumentation.java:1180)
    08-22 14:28:36.078: E/AndroidRuntime(509):  at android.app.ActivityThread.performPauseActivity(ActivityThread.java:3330)

更新：

提醒编辑活动：

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

import com.actionbarsherlock.app.SherlockActivity;
import com.actionbarsherlock.view.MenuItem;

import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.app.TimePickerDialog;
import android.content.Intent;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.TimePicker;
import android.widget.Toast;

public class ReminderEditActivity extends SherlockActivity {

    // 
    // Dialog Constants
    //
    private static final int DATE_PICKER_DIALOG = 0;
    private static final int TIME_PICKER_DIALOG = 1;

    // 
    // Date Format 
    //
    private static final String DATE_FORMAT = "yyyy-MM-dd"; 
    private static final String TIME_FORMAT = "kk:mm";
    public static final String DATE_TIME_FORMAT = "yyyy-MM-dd kk:mm:ss";

    private EditText mTitleText;
    private EditText mBodyText;
    private Button mDateButton;
    private Button mTimeButton;
    private Button mConfirmButton;
    private Long mRowId;
    private RemindersDbAdapter mDbHelper;
    private Calendar mCalendar;  

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mDbHelper = new RemindersDbAdapter(this);

        setContentView(R.layout.reminder_edit);

        mCalendar = Calendar.getInstance(); 
        mTitleText = (EditText) findViewById(R.id.title);
        mBodyText = (EditText) findViewById(R.id.body);
        mDateButton = (Button) findViewById(R.id.reminder_date);
        mTimeButton = (Button) findViewById(R.id.reminder_time);


        mRowId = savedInstanceState != null ? savedInstanceState.getLong(RemindersDbAdapter.KEY_ROWID) 
                                            : null;

        registerButtonListenersAndSetDefaultText();

        com.actionbarsherlock.app.ActionBar aBar = getSupportActionBar();
        String dateString = (String) android.text.format.DateFormat.format("MMM d, yyyy", new java.util.Date());
        aBar.setTitle(dateString);
    }



    private void setRowIdFromIntent() {
        if (mRowId == null) {
            Bundle extras = getIntent().getExtras();            
            mRowId = extras != null ? extras.getLong(RemindersDbAdapter.KEY_ROWID) 
                                    : null;

        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        mDbHelper.close(); 
    }







    @Override
    public boolean onCreateOptionsMenu(com.actionbarsherlock.view.Menu menu) {
        // TODO Auto-generated method stub
         com.actionbarsherlock.view.MenuInflater inflater = getSupportMenuInflater();
            inflater.inflate(R.menu.edit, (com.actionbarsherlock.view.Menu) menu);
        return super.onCreateOptionsMenu(menu);

    }



    @Override
    public boolean onMenuItemSelected(int featureId,
            com.actionbarsherlock.view.MenuItem item) {
        // TODO Auto-generated method stub
        switch(item.getItemId()) {
        case R.id.accept: 
            saveState(); 
            setResult(RESULT_OK);
            Toast.makeText(ReminderEditActivity.this, getString(R.string.task_saved_message), Toast.LENGTH_SHORT).show();
            finish(); 
            return true; 
        case R.id.back:
            finish();
           // Intent i = new Intent(this, ReminderListActivity.class);
            //startActivity(i); 

        return super.onMenuItemSelected(featureId, item);}
        return true;
    }



    @Override
    protected void onResume() {
        super.onResume();
        mDbHelper.open(); 
        setRowIdFromIntent();
        populateFields();
    }

    @Override
    protected Dialog onCreateDialog(int id) {
        switch(id) {
            case DATE_PICKER_DIALOG: 
                return showDatePicker();
            case TIME_PICKER_DIALOG: 
                return showTimePicker(); 
        }
        return super.onCreateDialog(id);
    }

    private DatePickerDialog showDatePicker() {


        DatePickerDialog datePicker = new DatePickerDialog(ReminderEditActivity.this, new DatePickerDialog.OnDateSetListener() {

            @Override
            public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
                mCalendar.set(Calendar.YEAR, year);
                mCalendar.set(Calendar.MONTH, monthOfYear);
                mCalendar.set(Calendar.DAY_OF_MONTH, dayOfMonth);
                updateDateButtonText(); 
            }
        }, mCalendar.get(Calendar.YEAR), mCalendar.get(Calendar.MONTH), mCalendar.get(Calendar.DAY_OF_MONTH)); 
        return datePicker; 
    }

   private TimePickerDialog showTimePicker() {

        TimePickerDialog timePicker = new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener() {

            @Override
            public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
                mCalendar.set(Calendar.HOUR_OF_DAY, hourOfDay);
                mCalendar.set(Calendar.MINUTE, minute); 
                updateTimeButtonText(); 
            }
        }, mCalendar.get(Calendar.HOUR_OF_DAY), mCalendar.get(Calendar.MINUTE), true); 

        return timePicker; 
    }

    private void registerButtonListenersAndSetDefaultText() {

        mDateButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                showDialog(DATE_PICKER_DIALOG);  
            }
        }); 


        mTimeButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                showDialog(TIME_PICKER_DIALOG); 
            }
        }); 



          updateDateButtonText(); 
          updateTimeButtonText();
    }

    private void populateFields()  {



        // Only populate the text boxes and change the calendar date
        // if the row is not null from the database. 
        if (mRowId != null) {
            Cursor reminder = mDbHelper.fetchReminder(mRowId);
            startManagingCursor(reminder);
            mTitleText.setText(reminder.getString(
                    reminder.getColumnIndexOrThrow(RemindersDbAdapter.KEY_TITLE)));
            mBodyText.setText(reminder.getString(
                    reminder.getColumnIndexOrThrow(RemindersDbAdapter.KEY_BODY)));


            // Get the date from the database and format it for our use. 
            SimpleDateFormat dateTimeFormat = new SimpleDateFormat(DATE_TIME_FORMAT);
            Date date = null;
            try {
                String dateString = reminder.getString(reminder.getColumnIndexOrThrow(RemindersDbAdapter.KEY_DATE_TIME)); 
                date = dateTimeFormat.parse(dateString);
                mCalendar.setTime(date); 
            } catch (ParseException e) {
                Log.e("ReminderEditActivity", e.getMessage(), e); 
            } 
        } else {
            // This is a new task - add defaults from preferences if set. 
            SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this); 
            String defaultTitleKey = getString(R.string.pref_task_title_key); 
            String defaultTimeKey = getString(R.string.pref_default_time_from_now_key); 

            String defaultTitle = prefs.getString(defaultTitleKey, null);
            String defaultTime = prefs.getString(defaultTimeKey, null); 

            if(defaultTitle != null)
                mTitleText.setText(defaultTitle); 

            if(defaultTime != null)
                mCalendar.add(Calendar.MINUTE, Integer.parseInt(defaultTime));

        }

        updateDateButtonText(); 
        updateTimeButtonText(); 

    }

    private void updateTimeButtonText() {
        // Set the time button text based upon the value from the database
        SimpleDateFormat timeFormat = new SimpleDateFormat(TIME_FORMAT); 
        String timeForButton = timeFormat.format(mCalendar.getTime()); 
        mTimeButton.setText(timeForButton);
    }

    private void updateDateButtonText() {
        // Set the date button text based upon the value from the database 
        SimpleDateFormat dateFormat = new SimpleDateFormat(DATE_FORMAT); 
        String dateForButton = dateFormat.format(mCalendar.getTime()); 
        mDateButton.setText(dateForButton);
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putLong(RemindersDbAdapter.KEY_ROWID, mRowId);
    }



    private void saveState() {
        String title = mTitleText.getText().toString();
        String body = mBodyText.getText().toString();

        SimpleDateFormat dateTimeFormat = new SimpleDateFormat(DATE_TIME_FORMAT); 
        String reminderDateTime = dateTimeFormat.format(mCalendar.getTime());

        if (mRowId == null) {

            long id = mDbHelper.createReminder(title, body, reminderDateTime);
            if (id > 0) {
                mRowId = id;
            }
        } else {
            mDbHelper.updateReminder(mRowId, title, body, reminderDateTime);
        }

        new ReminderManager(this).setReminder(mRowId, mCalendar); 
    }

}

我更新了我的问题，这是我得到错误的活动。希望有人能找出错误...

4

1 回答 1

1

检查这一行

outState.putLong(RemindersDbAdapter.KEY_ROWID, mRowId);

mRowIdis Long（一个对象）和一个 puntLong()，采用long（一个不承认 null 的主要数据类型）。如果mRowId是null要崩溃。

于 2013-08-22T13:56:45.260 回答