[英]How to fix [The method put(String, Boolean) in the type ContentValues is not applicable for the arguments (Boolean, Boolean)]
I'm trying to learn how to develop an Android App and am trying to re-write Notepadv3Solution {http://developer.android.com/training/notepad/index.html}
from modifying it for my own purposes. 我正在尝试学习如何开发Android应用程序,并试图出于自己的目的修改
Notepadv3Solution {http://developer.android.com/training/notepad/index.html}
进行重写。
In the method createTask
(nr the bottom), I get the error The method put(String, Boolean) in the type ContentValues is not applicable for the arguments (Boolean, Boolean)
. 在方法
createTask
(底部为nr)中,出现错误The method put(String, Boolean) in the type ContentValues is not applicable for the arguments (Boolean, Boolean)
。 I've added a boolean field for the database, adding it also to the createTask
method. 我为数据库添加了一个布尔字段,并将其也添加到
createTask
方法中。 How can I get it the boolean field to work? 我怎样才能使布尔字段起作用?
package com.superiorxc.taskcentral;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class TasksDbAdapter {
public static final String KEY_ROWID = "_id";
public static final String KEY_TITLE = "title";
public static final String KEY_BODY = "body";
public static final Boolean KEY_COMPLETE = true;
private static final String TAG = "TasksDbAdapter";
private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;
/**
* Database creation sql statement
*/
private static final String DATABASE_CREATE =
"create table tbl_tasks (_id integer primary key autoincrement, "
+ "title text not null, body text, complete boolean not null);";
private static final String DATABASE_NAME = "db_taskcentral";
private static final String DATABASE_TABLE = "tbl_tasks";
private static final int DATABASE_VERSION = 1;
private final Context mCtx;
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(DATABASE_CREATE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS tbl_tasks");
onCreate(db);
}
}
/**
* Constructor - takes the context to allow the database to be
* opened/created
*
* @param ctx the Context within which to work
*/
public TasksDbAdapter(Context ctx) {
this.mCtx = ctx;
}
/**
* Open the db_taskcentral database. If it cannot be opened, try to create a new
* instance of the database. If it cannot be created, throw an exception to
* signal the failure
*
* @return this (self reference, allowing this to be chained in an
* initialization call)
* @throws SQLException if the database could be neither opened or created
*/
public TasksDbAdapter open() throws SQLException {
mDbHelper = new DatabaseHelper(mCtx);
mDb = mDbHelper.getWritableDatabase();
return this;
}
public void close() {
mDbHelper.close();
}
/**
* Create a new task using the title and body provided. If the task is
* successfully created return the new rowId for that note, otherwise return
* a -1 to indicate failure.
*
* @param title the title of the task
* @param body the body of the task
* @return rowId or -1 if failed
*/
public long createTask(String title, String body, Boolean complete) {
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_TITLE, title);
initialValues.put(KEY_BODY, body);
initialValues.put(KEY_COMPLETE,complete);
return mDb.insert(DATABASE_TABLE, null, initialValues);
}
}
Change KEY_COMPLETE
to 将
KEY_COMPLETE
更改为
public static final String KEY_COMPLETE = "complete";
You want it to reference what you named your column in the database. 您希望它引用您在数据库中命名的列。
You can think of ContentValues as a Map<String,Object>
where the key is the name of the database column and the object is what you want to put into the row for that column. 您可以将ContentValues视为
Map<String,Object>
,其中键是数据库列的名称,而对象是要放入该列的行中的对象。
If you are asking "How to convert a Boolean to a String" then the easiest way is this: 如果您询问“如何将布尔值转换为字符串”,那么最简单的方法是:
String.valueOf(Boolean)
as in the following code: 如以下代码所示:
Boolean b = false;
String aString = String.valueOf(b);
System.out.println(aString);
One solution would be to change 一种解决方案是改变
public static final Boolean KEY_COMPLETE = true;
to 至
public static final String KEY_COMPLETE = "true";
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