我是android和java的新手。我试图根据示例检查我的代码，但不知何故，当示例运行良好时，应用程序会强制关闭。我需要帮助！提前致谢！
新的 Logcat
07-31 16:51:02.145: E/Trace(16532): error opening trace file: No such file or directory (2)
07-31 16:51:02.175: D/AndroidRuntime(16532): Shutting down VM
07-31 16:51:02.180: W/dalvikvm(16532): threadid=1: thread exiting with uncaught exception (group=0x40fdb2a0)
07-31 16:51:02.180: E/AndroidRuntime(16532): FATAL EXCEPTION: main
07-31 16:51:02.180: E/AndroidRuntime(16532): java.lang.RuntimeException: Unable to create application com.Elson.ProjectVersion.ContactsActivityApplication: java.lang.NullPointerException
07-31 16:51:02.180: E/AndroidRuntime(16532): at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4254)
07-31 16:51:02.180: E/AndroidRuntime(16532): at android.app.ActivityThread.access$1400(ActivityThread.java:140)
07-31 16:51:02.180: E/AndroidRuntime(16532): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1297)
07-31 16:51:02.180: E/AndroidRuntime(16532): at android.os.Handler.dispatchMessage(Handler.java:99)
07-31 16:51:02.180: E/AndroidRuntime(16532): at android.os.Looper.loop(Looper.java:137)
07-31 16:51:02.180: E/AndroidRuntime(16532): at android.app.ActivityThread.main(ActivityThread.java:4921)
07-31 16:51:02.180: E/AndroidRuntime(16532): at java.lang.reflect.Method.invokeNative(Native Method)
07-31 16:51:02.180: E/AndroidRuntime(16532): at java.lang.reflect.Method.invoke(Method.java:511)
07-31 16:51:02.180: E/AndroidRuntime(16532): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
07-31 16:51:02.180: E/AndroidRuntime(16532): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
07-31 16:51:02.180: E/AndroidRuntime(16532): at dalvik.system.NativeStart.main(Native Method)
07-31 16:51:02.180: E/AndroidRuntime(16532): Caused by: java.lang.NullPointerException
07-31 16:51:02.180: E/AndroidRuntime(16532): at java.util.Calendar.setTime(Calendar.java:1324)
07-31 16:51:02.180: E/AndroidRuntime(16532): at java.text.SimpleDateFormat.formatImpl(SimpleDateFormat.java:536)
07-31 16:51:02.180: E/AndroidRuntime(16532): at java.text.SimpleDateFormat.format(SimpleDateFormat.java:821)
07-31 16:51:02.180: E/AndroidRuntime(16532): at java.text.DateFormat.format(DateFormat.java:376)
07-31 16:51:02.180: E/AndroidRuntime(16532): at com.Elson.ProjectVersion.Contacts.toString(Contacts.java:91)
07-31 16:51:02.180: E/AndroidRuntime(16532): at com.Elson.ProjectVersion.ContactsActivityApplication.readContactsFromDB(ContactsActivityApplication.java:57)
07-31 16:51:02.180: E/AndroidRuntime(16532): at com.Elson.ProjectVersion.ContactsActivityApplication.onCreate(ContactsActivityApplication.java:26)
07-31 16:51:02.180: E/AndroidRuntime(16532): at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:1014)
07-31 16:51:02.180: E/AndroidRuntime(16532): at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4251)
07-31 16:51:02.180: E/AndroidRuntime(16532): ... 10 more
联系人.java
package com.Elson.ProjectVersion;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteException;
import android.util.Log;
public class Contacts implements Comparable<Contacts> {
private long id;
private String name;
private int Phone;
private int Email;
private Date date;
private double runningAverage;
public Contacts(String name, int Phone, Date date) {
this.name = name;
this.Phone = Phone;
this.date = date;
}
public Contacts(long id, String name,int Phone) {
this.id=id;
this.Phone=Phone;
this.name= (name);
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public int getPhone() {
return Phone;
}
public void setPhone(int Phone) {
this.Phone = Phone;
}
public String getname() {
return name;
}
public void setname(String name) {
this.name = name;
}
public Date getDate() {
return date;
}
public long getDateEpoch(){
return date.getTime()/1000;
}
public void setDateEpoch(long seconds){
date= new Date (seconds*1000);
}
public void setDate(Date date) {
this.date = date;
}
public void setRunningAverage(double runningAverage) {
this.runningAverage = runningAverage;
}
public boolean equals(Object that){
Contacts bs = (Contacts) that;
return this.date.equals(bs.date);
}
@Override
public String toString() {
String result;
// "ID" + id +" "
DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT);
result = df.format(date) + "" + name + "" + Phone ;
return result;
}
@Override
public int compareTo(Contacts another) {
// TODO Auto-generated method stub
return 0;
}
}
联系人ActivityApplication
package com.Elson.ProjectVersion;
import java.util.ArrayList;
import android.app.Application;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
import static com.Elson.ProjectVersion.MyContactSQL.*;
public class EnterContactsActivity extends Activity {
private Button saveButton;
private EditText NameEditText;
private EditText PhoneEditText;
private Button ExitButton;
private EditText EmailEditText;
private TextView date;
private int month;//private within class
private int day;
private int year;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_addcontacts);
setUpViews();
Calendar calendar =Calendar.getInstance();
year = calendar.get(Calendar.YEAR);
month = calendar.get(Calendar.MONTH);
day = calendar.get(Calendar.DAY_OF_MONTH);
Date today = calendar.getTime();
DateFormat df = DateFormat.getDateInstance(DateFormat.MEDIUM);
String cs = df.format(today);
date.setText(cs);
}
public void saveClickHandler(View v){
String ContactsScore;
ContactsScore= NameEditText.getText().toString();
String name = String.format(ContactsScore, null);
ContactsScore= PhoneEditText.getText().toString();
int Phone = Integer.parseInt(ContactsScore);
Log.d("EnterContacts" , "I hear the Save Button");
if( isValid(Phone) ) {
Contacts contacts;
Date dateofGames= new GregorianCalendar(year,month,day).getTime();
contacts = new Contacts (name , Phone , dateofGames);
ContactsActivityApplication app = (ContactsActivityApplication) getApplication();
//might be wrong
Log.d("DeBUGGING", "app is this type: " + app.getClass().getName());
//need add the function addBowlingScores
app.addallContacts(contacts);
Toast.makeText(getApplicationContext(), "Your Contact has been Saved!", Toast.LENGTH_SHORT).show();
}
else{
//pop up a dialog that data is invalid
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Invalid Phone Number")
.setMessage("Phone numbers cannot have more than 8 numbers")
.setCancelable(false)
.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();
}
}
private boolean isValid(int Phone ) {
if(Phone > 0 && Phone <100000000)
return true;
return false;
// TODO Auto-generated method stub
}
public void handleShowHistoryClick (View v) {
Intent intent = new Intent(this, HistoryActivity.class);
startActivity(intent);
}
private void setUpViews()
{
ExitButton = (Button) findViewById(R.id.BtnExit);
saveButton =(Button) findViewById(R.id.BtnSave);
NameEditText= (EditText) findViewById(R.id.NameEditText);
PhoneEditText= (EditText) findViewById(R.id.PhoneEditText);
EmailEditText= (EditText) findViewById(R.id.EmailEditText);
date = (TextView) findViewById(R.id.DateTextView);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.addcontacts, menu);
return true;
}
}
EnterContactsActivity
package com.Elson.ProjectVersion;
import java.text.DateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import android.os.Bundle;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class EnterContactsActivity extends Activity {
private Button saveButton;
private EditText NameEditText;
private EditText PhoneEditText;
private Button ExitButton;
private EditText EmailEditText;
private TextView date;
private int month;//private within class
private int day;
private int year;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_addcontacts);
setUpViews();
Calendar calendar =Calendar.getInstance();
year = calendar.get(Calendar.YEAR);
month = calendar.get(Calendar.MONTH);
day = calendar.get(Calendar.DAY_OF_MONTH);
Date today = calendar.getTime();
DateFormat df = DateFormat.getDateInstance(DateFormat.MEDIUM);
String cs = df.format(today);
date.setText(cs);
}
public void saveClickHandler(View v){
String ContactsScore;
ContactsScore= NameEditText.getText().toString();
int name = Integer.parseInt(ContactsScore);
ContactsScore= PhoneEditText.getText().toString();
int Phone = Integer.parseInt(ContactsScore);
ContactsScore = EmailEditText.getText().toString();
int Email = Integer.parseInt(ContactsScore);
Log.d("EnterContacts" , "I hear the Save Button");
if( isValid(name) && isValid(Phone) && isValid(Email) ) {
Contacts contacts;
Date dateofGames= new GregorianCalendar(year,month,day).getTime();
contacts = new Contacts (name , Phone , Email, dateofGames);
ContactsActivityApplication app = (ContactsActivityApplication) getApplication();
//might be wrong
Log.d("DeBUGGING", "app is this type: " + app.getClass().getName());
//need add the function addBowlingScores
app.addallContacts(contacts);
Toast.makeText(getApplicationContext(), "Your Contact has been Saved!", Toast.LENGTH_SHORT).show();
}
else{
//pop up a dialog that data is invalid
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Invalid Phone Number")
.setMessage("Phone numbers cannot have more than 8 numbers")
.setCancelable(false)
.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();
}
}
private boolean isValid(int phone) {
if(phone <= 0 && phone >=100000000)
return true;
return false;
// TODO Auto-generated method stub
}
private void setUpViews()
{
ExitButton = (Button) findViewById(R.id.BtnExit);
saveButton =(Button) findViewById(R.id.BtnSave);
NameEditText= (EditText) findViewById(R.id.NameEditText);
PhoneEditText= (EditText) findViewById(R.id.PhoneEditText);
EmailEditText= (EditText) findViewById(R.id.EmailEditText);
date = (TextView) findViewById(R.id.DateTextView);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.addcontacts, menu);
return true;
}
}
我的联系人SQL
package com.Elson.ProjectVersion;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteException;
import android.util.Log;
公共类 MyContactSQL 扩展 SQLiteOpenHelper {
public static final String DB_NAME ="MyContactSQL.SQLite";
public static final int DB_VERSION = 1;
public static String CONTACT_LIST_TABLE = "ContactListTable";
public static String RECORD_ID ="ID";
public static String NAME = "NAME";
public static String PHONE_NUMBER="PhoneNumber";
public MyContactSQL(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase contactListDB) {
String sqlStatement = "create table " + CONTACT_LIST_TABLE
+ " ("
+ RECORD_ID + " integer primary key autoincrement not null,"
+ NAME + " long,"
+ PHONE_NUMBER +" integer"
+");";
Log.d("Contact Database", sqlStatement);
contactListDB.execSQL(sqlStatement);
}
@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
}
}
历史活动
import java.util.ArrayList;
import android.app.AlertDialog;
import android.app.ListActivity;
import android.content.DialogInterface;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class HistoryActivity extends ListActivity {
Bundle savedInstanceState;
private ArrayList <Contacts> allContacts;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.savedInstanceState = savedInstanceState;
setContentView(R.layout.history_layout);
//get data from the App
ContactsActivityApplication app = (ContactsActivityApplication) getApplication();
allContacts = app.getAllContacts();
//View --- Adapter ------ Data
setListAdapter(
new ArrayAdapter<Contacts> (this, R.layout.history_row,
allContacts
));
ListView listView = this.getListView();
listView.setOnItemClickListener(
new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
verifyDeleteRow(position);
Log.d("DEBUG", "I hear item selected:" + position);
// TODO Auto-generated method stub
}
}
);
}
private void verifyDeleteRow(final int position){
//pop up a dialog to confirm delete row
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Delete this Series?")
.setMessage("Do you want to delete this data?" + allContacts.get(position))
.setCancelable(false)
.setNegativeButton("NO! Leave it there!",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
dialog.cancel();
}
})
.setPositiveButton("Delete",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Contacts toDelete = allContacts.get(position);
ContactsActivityApplication app = (ContactsActivityApplication) getApplication();
app.deleteBowlingScores(toDelete);
// TODO Auto-generated method stub
onCreate(savedInstanceState);
}
});
AlertDialog alert = builder.create();
alert.show();
}
}