我正在为一家理发店建立一个应用程序，我现在正在创建一个约会并保存该约会的数据，但是当我去点击添加创建约会时，应用程序崩溃了我离开了这个错误;
Condition 1 - If at least one rate IN (0.01, 0.015, 0.05) for this ID THEN replace all 0 values by the most rate values (e.g. if for this ID, 0.01 appears more than 0.05 then replace 0 with 0.01. Only rates == 0 rows can be replaced)
Condition 2 - If rates NOT IN (0.01, 0.015, 0.05) then make no changes to the rows
这是 TableControllerAppointments.java
的课程E/CursorWindow: Failed to read row 0, column -1 from a CursorWindow which has 2 rows, 3 columns.
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: ie.app.barbershop, PID: 31270
java.lang.IllegalStateException: Couldn't read row 0, col -1 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it.
at android.database.CursorWindow.nativeGetString(Native Method)
at android.database.CursorWindow.getString(CursorWindow.java:438)
at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:51)
at ie.app.barbershop.TableControllerAppointments.read(TableControllerAppointments.java:46)
at ie.app.barbershop.Landing.readRecords(Landing.java:47)
at ie.app.barbershop.OnClickListenerCreateAppointment$1.onClick(OnClickListenerCreateAppointment.java:38)
at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:162)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
I/Process: Sending signal. PID: 31270 SIG: 9
Application terminated.
这是我的 OnClickListenerCreateAppointment.java
的课程package ie.app.barbershop;
import android.content.Context;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import java.util.ArrayList;
import java.util.List;
public class TableControllerAppointments extends DatabaseHandler {
public TableControllerAppointments(Context context) {
super(context);
}
public boolean create(ObjectAppointment objectAppointments) {
ContentValues values = new ContentValues();
values.put("fullname", objectAppointments.fullName);
values.put("contactno", objectAppointments.contactNumber);
SQLiteDatabase db = this.getWritableDatabase();
boolean createSuccessful = db.insert("appointments", null, values) > 0;
db.close();
return createSuccessful;
}
public List<ObjectAppointment> read() {
List<ObjectAppointment> recordsList = new ArrayList<>();
String sql = "SELECT * FROM Appointments ORDER BY id DESC";
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(sql, null);
if (cursor.moveToFirst()) {
do {
String fullName = cursor.getString(cursor.getColumnIndex("firstname"));
int contactNumber = Integer.parseInt(cursor.getString(cursor.getColumnIndex("contactno")));
ObjectAppointment objectAppointment = new ObjectAppointment();
objectAppointment.fullName = fullName;
objectAppointment.contactNumber = contactNumber;
recordsList.add(objectAppointment);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return recordsList;
}
public int count() {
SQLiteDatabase db = this.getWritableDatabase();
String sql = "SELECT * FROM appointments";
int recordCount = db.rawQuery(sql, null).getCount();
db.close();
return recordCount;
}
}
这是我的 Landing.java类
package ie.app.barbershop;
import android.view.View;
import android.content.Context;
import android.view.LayoutInflater;
import android.widget.EditText;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.widget.Toast;
public class OnClickListenerCreateAppointment implements View.OnClickListener {
public ObjectAppointment objectAppointment;
@Override
public void onClick(View view){
final Context context = view.getRootView().getContext();
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
final View formElementsView = inflater.inflate(R.layout.appointment_input_form, null, false);
final EditText editTextFullName = formElementsView.findViewById(R.id.editTextFullName);
final EditText editTextContactNumber = formElementsView.findViewById(R.id.editTextContactNumber);
ObjectAppointment objectAppointment = new ObjectAppointment();
new AlertDialog.Builder(context)
.setView(formElementsView)
.setTitle("Create Appointment")
.setPositiveButton("Add",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
String fullname = editTextFullName.getText().toString();
String contactno = editTextContactNumber.getText().toString();
((Landing) context).countRecords();
((Landing) context).readRecords();
dialog.cancel();
}
}).show();
boolean createSuccessful = new TableControllerAppointments(context).create(objectAppointment);
if(createSuccessful){
Toast.makeText(context, "Appointment Information was saved.", Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(context, "Unable to save appointment information", Toast.LENGTH_SHORT).show();
}
}
}
数据库处理程序类
package ie.app.barbershop;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ScrollView;
import android.widget.TextView;
import java.util.List;
public class Landing extends AppCompatActivity{
public Button buttonProducts;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.content_landing);
countRecords();
buttonProducts = findViewById(R.id.buttonProducts);
Button buttonCreateAppointment = findViewById(R.id.buttonCreateAppointment);
buttonCreateAppointment.setOnClickListener(new OnClickListenerCreateAppointment());
buttonProducts.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(Landing.this, Products.class));
}
});
}
public void readRecords() {
LinearLayout linearLayoutRecords = findViewById(R.id.linearLayoutRecords);
linearLayoutRecords.removeAllViews();
List<ObjectAppointment> appointments = new TableControllerAppointments(this).read();
if (appointments.size() > 0) {
for (ObjectAppointment obj : appointments) {
String fullName = obj.fullName;
int contactNumber = obj.contactNumber;
String textViewContents = fullName + " - " + contactNumber;
TextView textViewAppointmentItem= new TextView(this);
textViewAppointmentItem.setPadding(0, 10, 0, 10);
textViewAppointmentItem.setText(textViewContents);
textViewAppointmentItem.setTag(Integer.toString(contactNumber));
linearLayoutRecords.addView(textViewAppointmentItem);
}
}
else {
TextView locationItem = new TextView(this);
locationItem.setPadding(8, 8, 8, 8);
locationItem.setText("No records yet.");
linearLayoutRecords.addView(locationItem);
}
}
public void countRecords(){
int recordCount = new TableControllerAppointments(this).count();
TextView textViewRecordCount = findViewById(R.id.textViewRecordCount);
textViewRecordCount.setText(recordCount + " records found.");
}
}
答案 0 :(得分：0)
从getColumnIndex返回-1意味着列 firstname 在下一行的光标中不存在。
String fullName = cursor.getString(cursor.getColumnIndex("firstname"));
使用以下方法创建表： -
String sql = "CREATE TABLE appointments " +
"( id INTEGER PRIMARY KEY AUTOINCREMENT, " +
"fullname TEXT, " +
"contactno NUMBER ) ";
其中列为id fullname和contactno。
-
要修复此更改以使用： -
String fullName = cursor.getString(cursor.getColumnIndex("fullname"));
最好还是将列和表名定义为常量，并始终引用它们。
e.g。
public class DatabaseHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
protected static final String DATABASE_NAME = "AppointmentDatabase";
public static final String TABLE_NAME = "appointments";
public static final String COL_ID = "id";
public static final String COl_FULLNAME = "fullname";
public static final String COL_CONTACTNO = "contactno";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
String sql = "CREATE TABLE " + TABLE_NAME +
"( " + COL_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
COL_FULLNAME + " TEXT, " +
COL_CONTACTNO + " NUMBER ) ";
db.execSQL(sql);
}
.... and so on
以后作为一个例子： -
String fullName = cursor.getString(cursor.getColumnIndex(DatabaseHandler.COL_FULLNAME));