java sqlite数据库不工作错误638
每当我想在安卓上向数据库列添加一行时,它都会给我一个致命错误,LogCat不会告诉我是什么导致了这个问题。它只告诉我文件和PID,同时也告诉我这是一个致命错误,PID编号是638
基本上,我需要一个对话框来显示用户需要填写的输入字段,以便将约会添加到数据库中
代码:
package com.example.calendar;
import 安卓.os.Bundle;
import 安卓.view.View;
import 安卓.view.View.OnClickListener;
import 安卓.widget.CalendarView;
import 安卓.widget.EditText;
import 安卓.app.Activity;
import 安卓.content.Intent;
import static 安卓.provider.BaseColumns._ID;
import static com.example.calendar.Constants.TABLE_NAME;
import static com.example.calendar.Constants.TIME;
import static com.example.calendar.Constants.TITLE;
import static com.example.calendar.Constants.DETAILS;
import static com.example.calendar.Constants.DATE;
import static com.example.calendar.Constants.CONTENT_URI;
import 安卓.content.ContentValues;
import 安卓.database.Cursor;
import 安卓.database.sqlite.SQLiteDatabase;
public class CreateAppointment extends Activity implements OnClickListener{
private static String[] FROM = { _ID, DATE, TIME, TITLE, DETAILS};
private static String ORDER_BY = TIME + " ASC";
private AppointmentsData appointments;
CalendarView calendar;
String string;
EditText nameTextBox;
EditText timeTextBox;
EditText detailsTextBox;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.create);
View createButton = findViewById(R.id.apptSave);
View nameTextBox = (EditText)findViewById(R.id.apptName);
View timeTextBox = (EditText)findViewById(R.id.apptTime);
View detailsTextBox = (EditText)findViewById(R.id.apptDetails);
calendar = (CalendarView)findViewById(R.id.calendar);
createButton.setOnClickListener(this);
}
private void addAppointment(String string) {
/* Insert a new record into the Events data
source. You would do something similar
for delete and update. */
String getTitle = nameTextBox.toString();
String getTime = timeTextBox.toString();
String getDetails = detailsTextBox.toString();
SQLiteDatabase db = appointments.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(DATE, calendar.getDate());
values.put(TIME, getTime);
values.put(TITLE, getTitle);
values.put(DETAILS, getDetails);
getContentResolver().insert(CONTENT_URI, values);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch(v.getId()){
case R.id.apptSave:
addAppointment(string);
finish();
break;
}
}
}
堆栈跟踪:
03-17 15:32:21.547: E/AndroidRuntime(638): FATAL EXCEPTION: main
03-17 15:32:21.547: E/AndroidRuntime(638): java.lang.NullPointerException
03-17 15:32:21.547: E/AndroidRuntime(638): at com.example.calendar.CreateAppointment.addAppointment(CreateAppointment.java:51)
03-17 15:32:21.547: E/AndroidRuntime(638): at com.example.calendar.CreateAppointment.onClick(CreateAppointment.java:70)
03-17 15:32:21.547: E/AndroidRuntime(638): at 安卓.view.View.performClick(View.java:3480)
03-17 15:32:21.547: E/AndroidRuntime(638): at 安卓.view.View$PerformClick.run(View.java:13983)
03-17 15:32:21.547: E/AndroidRuntime(638): at 安卓.os.Handler.handleCallback(Handler.java:605)
03-17 15:32:21.547: E/AndroidRuntime(638): at 安卓.os.Handler.dispatchMessage(Handler.java:92)
03-17 15:32:21.547: E/AndroidRuntime(638): at 安卓.os.Looper.loop(Looper.java:137)
03-17 15:32:21.547: E/AndroidRuntime(638): at 安卓.app.ActivityThread.main(ActivityThread.java:4340)
03-17 15:32:21.547: E/AndroidRuntime(638): at java.lang.reflect.Method.invokeNative(Native Method)
03-17 15:32:21.547: E/AndroidRuntime(638): at java.lang.reflect.Method.invoke(Method.java:511)
03-17 15:32:21.547: E/AndroidRuntime(638): at com.安卓.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
03-17 15:32:21.547: E/AndroidRuntime(638): at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:551)
03-17 15:32:21.547: E/AndroidRuntime(638): at dalvik.system.NativeStart.main(Native Method)
请帮忙
# 1 楼答案
您已经在
onCreate
中重新声明了变量,使其成为onCreate
的局部变量,其中作为实例的变量未初始化因此NPE
CreateAppointment.java
第51行可能是String getTitle = nameTextBox.toString();
换成
改变这个
到
编辑:
看到这个了吗
仅声明未初始化
您尚未初始化
string
您尚未初始化
appointments
因此你得到了NPE