SQLiteDatabase更新不工作？ [英] SQLiteDatabase update not working?
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问题描述
我想让db.update用新的值更新我的数据库的一行，但似乎没有保存。我已经查看了我的语法，但我似乎无法获取数据保存。插入功能正在工作，但不更新。任何帮助将不胜感激。下面是我的数据类，它使用一个DbHelper对象。
public class Data {
static final String TAG =Data;
public static final String DB_NAME =data.db;
public static final String TABLE_NAME =tasks;
public static final String C_ID =_id;
public static final String C_TASK =taskname;
public static final String C_DUE_DATE =due_date;
public static final String C_PRIORITY =priority;
public static final int DB_VERSION = 1;
上下文上下文;
DbHelper dbHelper;
SQLiteDatabase db;
public数据（上下文上下文）{
this.context = context;
dbHelper = new DbHelper（）;
}
public void insert（ToDoItem task）{
db = dbHelper.getWritableDatabase（）;
ContentValues values = new ContentValues（）;
values.put（C_TASK，task.getTask（））;
values.put（C_PRIORITY，task.getPriority（））;
db.insert（TABLE_NAME，null，values）;
}
public void update（int id，ToDoItem task）{
ContentValues values = new ContentValues（）;
values.put（C_ID，id）;
values.put（C_TASK，task.getTask（））;
values.put（C_PRIORITY，task.getPriority（））;
String [] whereArgs = {String.valueOf（id）};
db.update（TABLE_NAME，values，C_ID +=？，whereArgs）;
System.out.println（db.update（TABLE_NAME，values，C_ID +=？，whereArgs））;
Log.d（TAG，更新任务+ db.toString（）++ id +优先级+ task.getPriority
}
public void delete（int id）{
db.delete（TABLE_NAME，C_ID +=+ id，null）;
}
public Cursor queueAll（）{
db = dbHelper.getWritableDatabase（）;
String [] columns = new String [] {C_ID，C_TASK，C_DUE_DATE，C_PRIORITY};
游标cursor = db.query（TABLE_NAME，columns，
null，null，null，null，null）;
return cursor;
}
class DbHelper extends SQLiteOpenHelper {
public DbHelper（）{
super（context，DB_NAME，null，DB_VERSION）;
}
@Override
public void onCreate（SQLiteDatabase db）{
String sql = String.format（create table％s+
（％s int primary key，％s text，％s text，％s int），
TABLE_NAME，C_ID，C_TASK，C_DUE_DATE，C_PRIORITY）;
Log.d（TAG，onCreate with SQL：+ sql）;
db.execSQL（sql）;
}
@Override
public void onUpgrade（SQLiteDatabase db，int oldVersion，int newVersion）{
db.execSQL（drop if exists+ TABLE_NAME）;
onCreate（db）;
}
}
}
ToDoItem对象类我试图更新项目被点击时的优先级
public class ToDoItem {
private String任务;
private String dueDate;
private int priority;
public ToDoItem（String task）{
this.task = task;
this.priority = 1;
}
public ToDoItem（String task，String dueDate）{
this.task = task;
this.dueDate = dueDate;
this.priority = 1;
}
public ToDoItem（String task，int priority）{
this.task = task;
if（priority< = 3&& amp; priority> 0）{
this.priority = priority;
} else
this.priority = 1;
}
public ToDoItem（String task，String dueDate，int priority）{
this.task = task;
this.dueDate = dueDate;
if（priority< = 3&& amp; priority> 0）{
this.priority = priority;
} else
this.priority = 1;
}
public String getTask（）{
return task;
}
public void setTask（String task）{
this.task = task;
}
public String getDueDate（）{
return dueDate;
}
public void setDueDate（String dueDate）{
this.dueDate = dueDate;
}
public int getPriority（）{
return priority;
}
public void setPriority（int priority）{
if（priority< = 3&& priority> 0）{
this.priority =优先;
} else
this.priority = 1;
}
}
最后这里是我的onListItemClickListener它使用一个ArrayList ToDoItems ，更改优先级并从我的数据类调用update方法。但是，我试图更新的行的值保持不变。我使用Log.d检查是否正确的值被传递和他们是。由于某些原因，更改不会发生。任何帮助将不胜感激。
todoList.setOnItemClickListener（new AdapterView.OnItemClickListener（）{
@覆盖
public void onItemClick（AdapterView<？> arg0，View arg1，final int arg2，
long arg3）{
if（soundEnabled）{
playSound ）;
}
//更改arrayList中项目的优先级todoItems
todoItems.get（arg2）.setPriority（todoItems.get（arg2）.getPriority + 1）;
String name = todoItems.get（arg2）.getTask（）;
int priority = todoItems.get（arg2）.getPriority（）;
final ToDoItem task = new ToDoItem （name，priority）;
//获取数据库中任务的位置
int id = arg2 + 1;
data.update（id，task）;
}）;
解决方案
是否打印db.update ，C_ID +=+ id，null）函数返回值？
如果返回值为0，那么在DB中没有这样的id行记录。
I am trying to get db.update to update one of the rows of my database with new values but it does not seem to be saving. I have looked over my syntax but I cannot seem to get the data to save. The insert function is working but not update. Any help would be appreciated. Below is my data class which uses a DbHelper object.
public class Data {
static final String TAG = "Data";
public static final String DB_NAME = "data.db";
public static final String TABLE_NAME = "tasks";
public static final String C_ID = "_id";
public static final String C_TASK = "taskname";
public static final String C_DUE_DATE = "due_date";
public static final String C_PRIORITY = "priority";
public static final int DB_VERSION = 1;
Context context;
DbHelper dbHelper;
SQLiteDatabase db;
public Data(Context context) {
this.context = context;
dbHelper = new DbHelper();
}
public void insert(ToDoItem task) {
db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(C_TASK, task.getTask());
values.put(C_PRIORITY, task.getPriority());
db.insert(TABLE_NAME, null, values);
}
public void update(int id, ToDoItem task) {
ContentValues values = new ContentValues();
values.put(C_ID, id);
values.put(C_TASK, task.getTask());
values.put(C_PRIORITY, task.getPriority());
String[] whereArgs = {String.valueOf(id)};
db.update(TABLE_NAME, values, C_ID +" =?", whereArgs);
System.out.println(db.update(TABLE_NAME, values, C_ID +" =?", whereArgs));
Log.d(TAG, "updating task " + db.toString() +" "+ id + " to priority " + task.getPriority());
}
public void delete(int id){
db.delete(TABLE_NAME, C_ID+"="+id, null);
}
public Cursor queueAll(){
db = dbHelper.getWritableDatabase();
String[] columns = new String[]{C_ID, C_TASK, C_DUE_DATE, C_PRIORITY};
Cursor cursor = db.query(TABLE_NAME, columns,
null, null, null, null, null);
return cursor;
}
class DbHelper extends SQLiteOpenHelper {
public DbHelper() {
super(context, DB_NAME, null, DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
String sql = String.format("create table %s" +
"(%s int primary key, %s text, %s text, %s int)",
TABLE_NAME, C_ID, C_TASK, C_DUE_DATE, C_PRIORITY);
Log.d(TAG, "onCreate with SQL:"+sql);
db.execSQL(sql);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("drop if exists " + TABLE_NAME);
onCreate(db);
}
}
}
Here is the ToDoItem object class I am trying to update the priority when an item is clicked
public class ToDoItem {
private String task;
private String dueDate;
private int priority;
public ToDoItem(String task) {
this.task = task;
this.priority = 1;
}
public ToDoItem(String task, String dueDate) {
this.task = task;
this.dueDate = dueDate;
this.priority = 1;
}
public ToDoItem(String task, int priority) {
this.task = task;
if(priority <=3 && priority > 0) {
this.priority = priority;
} else
this.priority = 1;
}
public ToDoItem(String task, String dueDate, int priority) {
this.task = task;
this.dueDate = dueDate;
if(priority <=3 && priority > 0) {
this.priority = priority;
} else
this.priority = 1;
}
public String getTask() {
return task;
}
public void setTask(String task) {
this.task = task;
}
public String getDueDate() {
return dueDate;
}
public void setDueDate(String dueDate) {
this.dueDate = dueDate;
}
public int getPriority() {
return priority;
}
public void setPriority(int priority) {
if(priority <=3 && priority > 0) {
this.priority = priority;
} else
this.priority = 1;
}
}
Finally here is my onListItemClickListener it uses an ArrayList of ToDoItems, changes the priority and calls the update method from my data class. However the values of the row that I am trying to update remain unchanged. I used Log.d to check if the correct values were being passed and they were. For some reason the changes are not happening. Any help would be appreciated.
todoList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, final int arg2,
long arg3) {
if(soundEnabled) {
playSound();
}
// Change the priority of the item inside the arrayList todoItems
todoItems.get(arg2).setPriority(todoItems.get(arg2).getPriority() + 1);
String name = todoItems.get(arg2).getTask();
int priority = todoItems.get(arg2).getPriority();
final ToDoItem task = new ToDoItem(name, priority);
// Get the position of the task in the database
int id = arg2 + 1;
data.update(id, task);
});
解决方案
Would you print the db.update(TABLE_NAME, values, C_ID +"="+id, null) function return value?
If the return value is 0, so there is no such "id" row record in DB.
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