每当我查询数据以插入另一个活动时，我都会收到错误。
主要问题是我没有在堆栈跟踪中获得输出并成为新的程序员，我无法弄清楚发生了什么。
我是SQLite的新手，并不完全了解查询的工作原理，所以任何帮助都会受到赞赏。
如果我想点击Listview布局activity_main上的某个项目，就会出现此问题。
我已将onItemClickListener设置为将活动更改为edit_data布局，并且只要列表中的项目为，就会使用SQLite数据库表中的相应数据填充EditText字段点击。
但每当我点击某个项目时，它就会举起一个祝词：“没有与该名称相关联的ID”。
这个Toast消息由我自己内置到应用程序中，所以我知道什么是这个消息，但我不知道为什么。
这是我的代码：
MainActivity.java
package com.TheAbstractLightbulb.cohen.not_at_homes_app;
import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.content.Intent;
import android.view.View;
import android.widget.EditText;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;
public class MainActivity extends Activity {
private static final String TAG = "MainActivity";
DBHelper dbHelper;
public MainActivity() {
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
requestWindowFeature(Window.FEATURE_ACTION_BAR);
setContentView(R.layout.activity_main);
dbHelper = new DBHelper(this);
populateListView();
}
public void toInputScreen(View view) {
Button addButton = (Button) findViewById(R.id.addButton);
addButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent1 = new Intent(MainActivity.this, InputPage.class);
startActivity(intent1);
}
});
}
private void populateListView() {
Log.d(TAG, "populateListView: Displaying data in list view.");
final Cursor data = dbHelper.getData();
ArrayList<String> listData = new ArrayList<>();
while (data.moveToNext()) {
listData.add(data.getString(2));
}
ListView listview = (ListView) findViewById(R.id.MainListView);
final ListAdapter adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, listData);
listview.setAdapter(adapter);
listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
String map = adapterView.getItemAtPosition(i).toString();
String name = adapterView.getItemAtPosition(i).toString();
String date = adapterView.getItemAtPosition(i).toString();
String notAtHomes = adapterView.getItemAtPosition(i).toString();
Log.d(TAG, "onItemClick: You Clicked on " + notAtHomes);
Cursor data = dbHelper.getItemID(map, name, date, notAtHomes);
int itemID = -1;
while (data.moveToNext()) {
itemID = data.getInt(0);
}
if (itemID > -1) {
Log.d(TAG, "onItemClick: The ID is: " + itemID);
Intent editDataIntent = new Intent(MainActivity.this, EditData.class);
editDataIntent.putExtra("id", itemID);
editDataIntent.putExtra("map", map);
editDataIntent.putExtra("name", name);
editDataIntent.putExtra("date", date);
editDataIntent.putExtra("notAtHomes", notAtHomes);
startActivity(editDataIntent);
} else {
Toast.makeText(getBaseContext(), "No ID associated with that name", Toast.LENGTH_LONG).show();
}
}
});
}
}
EditData.java
package com.TheAbstractLightbulb.cohen.not_at_homes_app;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
/**
* Created by cohen on 2/06/2017.
*/
public class EditData extends Activity {
private static final String TAG = "EditData";
DBHelper dbhelper;
private int selectedID;
private String selectedMap;
private String selectedName;
private String selectedDate;
private String selectedNotAtHomes;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.edit_data);
final Button saveButton2 = (Button)findViewById(R.id.saveButton2);
Button deleteButton1 = (Button)findViewById(R.id.deleteButton1);
final EditText textNotAtHomes2 = (EditText)findViewById(R.id.textNotAtHomes2);
final EditText mapNoDisplay2 = (EditText)findViewById(R.id.mapNoDisplay2);
final EditText dateDisplay2 = (EditText)findViewById(R.id.dateDisplay2);
final EditText ListName2 = (EditText)findViewById(R.id.ListName2);
DBHelper DB = new DBHelper(this);
Intent receivedIntent = getIntent();
// ID
selectedID = receivedIntent.getIntExtra("id",-1);
// Map no
selectedMap = receivedIntent.getStringExtra("map");
// Name
selectedName = receivedIntent.getStringExtra("name");
// Date
selectedDate = receivedIntent.getStringExtra("date");
// Not at homes note file
selectedNotAtHomes = receivedIntent.getStringExtra("notAtHomes");
ListName2.setText(selectedName);
mapNoDisplay2.setText(selectedMap);
dateDisplay2.setText(selectedDate);
textNotAtHomes2.setText(selectedNotAtHomes);
saveButton2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String item1 = ListName2.getText().toString();
String item2 = mapNoDisplay2.getText().toString();
String item3 = dateDisplay2.getText().toString();
String item4 = textNotAtHomes2.getText().toString();
if (!item1.equals("")){
if (!item2.equals("")){
if (!item3.equals("")) {
if (!item4.equals("")) {
dbhelper.updateData(selectedID, item2, selectedMap, item1, selectedName, item3, selectedDate, item4, selectedNotAtHomes);
} else {
new AlertDialog.Builder(getBaseContext())
.setTitle("emptyBoxes")
.setMessage("Some boxes have been left empty, /n" +
"are you sure you are done?")
.setNegativeButton("Cancel", null)
.setPositiveButton("Save", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
}).create().show();
}
}
}
}
}
});
deleteButton1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
dbhelper.deleteData(selectedID, selectedMap, selectedName, selectedDate, selectedNotAtHomes);
Intent intent = new Intent(EditData.this, MainActivity.class);
startActivity(intent);
Toast.makeText(getBaseContext(), "Note Deleted successfully", Toast.LENGTH_LONG).show();
}
});
}
private void toSendNote(View view){
Button sendButton = (Button)findViewById(R.id.sendButton);
sendButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent1 = new Intent(EditData.this, SendRecord.class);
intent1.putExtra("Note", selectedNotAtHomes);
startActivity(intent1);
}
});
}
}
DBHelper.java
package com.TheAbstractLightbulb.cohen.not_at_homes_app;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
/**
* Created by cohen on 31/05/2017.
*/
public class DBHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "App_database.db";
public static final String TABLE_NAME = "App_date_table";
public static final String MAP_NO = "Map_no";
public static final String LOCATION = "Location";
public static final String DATE = "Date";
public static final String NOTATHOMES = "Not_at_homes";
public static final String ID = "ID";
public static final String TAG = "DBHelper";
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
String createTable = "CREATE TABLE " + TABLE_NAME + "(ID INTEGER PRIMARY KEY AUTOINCREMENT, " + MAP_NO + " INTEGER, " + LOCATION + " TEXT, " + DATE + " INTEGER, " + NOTATHOMES + " TEXT)";
db.execSQL(createTable);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
onCreate(db);
}
public boolean insertData(String Map_no, String Location, String Date, String Not_at_homes) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(MAP_NO, Map_no);
contentValues.put(LOCATION, Location);
contentValues.put(DATE, Date);
contentValues.put(NOTATHOMES, Not_at_homes);
Log.d(TAG, "addData: Adding " + Location + " to " + TABLE_NAME);
long result = db.insert(TABLE_NAME, null, contentValues);
if (result == -1) {
return false;
} else {
return true;
}
}
public Cursor getData() {
SQLiteDatabase db = this.getWritableDatabase();
String query = "SELECT * FROM " + TABLE_NAME;
Cursor data = db.rawQuery(query, null);
return data;
}
public Cursor getItemID(String map, String location, String date, String notAtHomes) {
SQLiteDatabase db = this.getWritableDatabase();
String query = "SELECT " + ID + " FROM " + TABLE_NAME +
" WHERE " + MAP_NO + " = '" + map + "' AND " + LOCATION + " = '" + location +
"' AND " + DATE + " = '" + date + "' AND "
+ NOTATHOMES + " = '" + notAtHomes + "'";
Cursor data = db.rawQuery(query, null);
return data;
}
public void updateData(int id,String newMapNo, String oldMapNo, String newLocation, String oldLocation, String newDate, String oldDate, String newNotAtHomes, String oldNotAtHomes){
SQLiteDatabase db = this.getWritableDatabase();
String query = "UPDATE " + TABLE_NAME + " SET " + MAP_NO +
" = '" + newMapNo + " WHERE " + ID + " = '" + id + "'" +
" AND " + MAP_NO + " = '" + oldMapNo + "'"+ LOCATION +
" = '" + newLocation + " WHERE " + ID + " = '" + id + "'" +
" AND " + LOCATION + " = '" + oldLocation + "'"+ DATE +
" = '" + newDate + " WHERE " + ID + " = '" + id + "'" +
" AND " + DATE + " = '" + oldDate + "'"+ NOTATHOMES +
" = '" + newNotAtHomes + " WHERE " + ID + " = '" + id + "'" +
" AND " + NOTATHOMES + " = '" + oldNotAtHomes + "'";
Log.d(TAG, "updating: query: " + query);
Log.d(TAG, "updating: Setting map number, Location, Date and Not at homes to new values: Map number: " +
newMapNo + " Location: " + newLocation + " Date: " +
newDate + " Not at homes: " + newNotAtHomes);
db.execSQL(query);
}
public void deleteData(int id, String mapNo, String location, String date, String notAtHomes){
SQLiteDatabase database = this.getWritableDatabase();
String query = "DELETE FROM " + TABLE_NAME + " WHERE "
+ ID + " + '" + id + "'" + " AND " + MAP_NO + " = '" + mapNo + "'" +
LOCATION + " = '" + location + "'" + DATE + " = '" + date + "'" + NOTATHOMES +
" = '" + notAtHomes + "'";
Log.d(TAG, "deleting: query: " + query);
Log.d(TAG, "deleting: Deleting note with values: Map number: " + mapNo + " Location: " + location + " Created on: " + date + " With notes: " + notAtHomes + ".");
database.execSQL(query);
}
}
MainActivity XML
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.TheAbstractLightbulb.cohen.not_at_homes_app.MainActivity"
android:background="@color/BackgroundGrey">
<Button
android:id="@+id/addButton"
android:layout_width="351dp"
android:layout_height="61dp"
android:layout_marginBottom="16dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="8dp"
android:layout_marginStart="16dp"
android:layout_marginTop="449dp"
android:onClick="toInputScreen"
android:background="@drawable/buttons"
android:text="@string/ButtonAddButton"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.733"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0" />
<ListView
android:id="@+id/MainListView"
android:layout_width="336dp"
android:layout_height="521dp"
android:layout_marginBottom="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginTop="8dp"
android:divider="@color/blackText"
android:headerDividersEnabled="false"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.6"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
</android.support.constraint.ConstraintLayout>
EditData XML
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".EditData"
android:background="@color/BackgroundGrey">
<Button
android:id="@+id/saveButton2"
android:layout_width="110dp"
android:layout_height="66dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:background="@drawable/buttons"
android:onClick="toSaveField"
android:text="@string/saveButton"
android:textSize="16sp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.005"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0" />
<Button
android:id="@+id/deleteButton1"
android:layout_width="110dp"
android:layout_height="66dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:background="@drawable/buttons"
android:onClick="toDeleteNote"
android:text="@string/ButtonDeleteButton"
android:textSize="16sp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0" />
<Button
android:id="@+id/sendButton"
android:layout_width="110dp"
android:layout_height="66dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:background="@drawable/buttons"
android:onClick="toSendNote"
android:text="@string/sendButtonText"
android:textSize="16sp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0" />
<EditText
android:id="@+id/textNotAtHomes2"
android:layout_width="0dp"
android:layout_height="0dp"
android:ems="10"
android:background="@color/hintTextColour"
android:inputType="textMultiLine"
android:hint="@string/hintText2"
android:textColorHint="@color/hintTextColour2"
android:layout_marginLeft="9dp"
android:gravity="fill_horizontal"
android:padding="6dp"
app:layout_constraintLeft_toLeftOf="parent"
android:layout_marginRight="9dp"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginBottom="89dp"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="89dp"
tools:layout_constraintTop_creator="1"
tools:layout_constraintRight_creator="1"
tools:layout_constraintBottom_creator="1"
android:layout_marginStart="9dp"
android:layout_marginEnd="9dp"
tools:layout_constraintLeft_creator="1"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintVertical_bias="1.0" />
<EditText
android:id="@+id/ListName2"
android:layout_width="0dp"
android:layout_height="37dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:background="@color/BackgroundGrey2"
android:inputType="text"
android:textColor="@color/blackText"
android:textSize="20sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0"
tools:layout_constraintLeft_creator="1"
tools:layout_constraintRight_creator="1" />
<EditText
android:id="@+id/mapNoDisplay2"
android:layout_width="172dp"
android:layout_height="37dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:background="@color/BackgroundGrey2"
android:inputType="number"
android:textColor="@color/blackText"
android:textSize="20sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.065" />
<EditText
android:id="@+id/dateDisplay2"
android:layout_width="172dp"
android:layout_height="37dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:background="@color/BackgroundGrey2"
android:inputType="date"
android:textColor="@color/blackText"
android:textSize="20sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.065" />
</android.support.constraint.ConstraintLayout>
答案 0 :(得分：0)
目前还不清楚你在询问什么。这些都是完全相同的字符串
String map = adapterView.getItemAtPosition(i).toString();
String name = adapterView.getItemAtPosition(i).toString();
String date = adapterView.getItemAtPosition(i).toString();
String notAtHomes = adapterView.getItemAtPosition(i).toString();
因此，sqlite无法找到您传入dbHelper.getItemID的内容，返回无效的ID值。
我认为您正在寻找从适配器获取不同的数据，这是不可能的，因为您只将光标的第三列添加到适配器。
ArrayList<String> listData = new ArrayList<>();
while (data.moveToNext()) {
listData.add(data.getString(2));
}
您应该考虑使用CursorAdapter正确实现带有数据库的ListView