Android sqlite数据库未获得更新
我将通过以下代码更新我的数据库: 这就是我做这件事的方式。我不知道当我要连接到db时是否必须调用create database方法:Android sqlite数据库未获得更新,android,sqlite,android-sqlite,sqliteopenhelper,Android,Sqlite,Android Sqlite,Sqliteopenhelper,我将通过以下代码更新我的数据库: 这就是我做这件事的方式。我不知道当我要连接到db时是否必须调用create database方法: public int addDBfav(int id) { SQLiteDatabase sqLiteDatabase; DbHelper myDbHelper=new DbHelper(this); try{ myDbHelper.createDatabase();
public int addDBfav(int id)
{
SQLiteDatabase sqLiteDatabase;
DbHelper myDbHelper=new DbHelper(this);
try{
myDbHelper.createDatabase();
}catch (IOException e)
{
throw new Error("unable to create database");
}
myDbHelper.openDataBase();
sqLiteDatabase=myDbHelper.getReadableDatabase();
ContentValues contentValues=new ContentValues();
contentValues.put("fav",true);
int part= sqLiteDatabase.update("food",contentValues,"food_id = "+Integer.toString(id),null);
Log.i("success","successfuly done "+Integer.toString(part));
return part;
}
这是我的db助手:
package com.example.android.dezcook;
import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* Created by Android on 6/10/2016.
*/
public class DbHelper extends SQLiteOpenHelper {
public static final String DBNAME = "database.sqlite";
private static String DB_PATH;
private SQLiteDatabase myDataBase;
private final Context mycontext;
public DbHelper(Context context) {
super(context, DBNAME, null, 1);
this.mycontext = context;
DB_PATH = context.getFilesDir().getParentFile().getPath() + "/databases/";
}
public void createDatabase() throws IOException {
boolean dbExist = checkDataBase();
if (dbExist) {//database is exist
}
else{
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error Copying Database");
}
}
}
private boolean checkDataBase() {
SQLiteDatabase DBcheck=null;
String myPath=DB_PATH+DBNAME;
try
{
SQLiteDatabase.openDatabase(myPath,null,SQLiteDatabase.OPEN_READONLY);
}catch (SQLException e){}
if(DBcheck!=null)
{
DBcheck.close();
}
return DBcheck!=null;
}
private void copyDataBase() throws IOException
{
InputStream myInput=
mycontext.getAssets().open(DBNAME);
String outFileName=DB_PATH+DBNAME;
OutputStream myOutPut=new FileOutputStream(outFileName);
byte[] buffer=new byte[1024];
int length;
while ((length=myInput.read(buffer))>0)
{
myOutPut.write(buffer,0,length);
}
myOutPut.flush();
myOutPut.close();
myInput.close();
}
public void openDataBase() throws SQLException
{
String myPath=DB_PATH+DBNAME;
myDataBase=SQLiteDatabase.openDatabase(myPath,null,SQLiteDatabase.OPEN_READONLY);
}
public synchronized void close()
{
if(myDataBase!=null)
myDataBase.close();
super.close();
}
// It closes the database if it exists, and then calls super.close()
// which calls close() in the parent class. It is synchronized which means it cannot run in parallel,
// calls to that method are queud up to avoid corruption of database
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
这是我的美食课
public class Food implements Parcelable {
protected int txtid;
protected String txtName;
protected String txtDesc;
protected String txtImage;
protected boolean txtFav;
protected String items;
protected int converted_image;
public int getTxtid() {
return txtid;
}
public void setTxtid(int txtid) {
this.txtid = txtid;
}
public String getTxtName() {
return txtName;
}
public void setTxtName(String txtName) {
this.txtName = txtName;
}
public String getTxtDesc() {
return txtDesc;
}
public void setTxtDesc(String txtDesc) {
this.txtDesc = txtDesc;
}
public String getTxtImage() {
return txtImage;
}
public void setTxtImage(String txtImage) {
this.txtImage = txtImage;
}
public boolean isTxtFav() {
return txtFav;
}
public void setTxtFav(boolean txtFav) {
this.txtFav = txtFav;
}
public String getItems() {
return items;
}
public void setItems(String items) {
this.items = items;
}
public int getConverted_image() {
return converted_image;
}
public void setConverted_image(int converted_image) {
this.converted_image = converted_image;
}
protected Food(){}
protected Food(Parcel in) {
txtid = in.readInt();
txtName = in.readString();
txtDesc = in.readString();
txtImage = in.readString();
txtFav = in.readByte() != 0;
items = in.readString();
converted_image = in.readInt();
}
public static final Creator<Food> CREATOR = new Creator<Food>() {
@Override
public Food createFromParcel(Parcel in) {
return new Food(in);
}
@Override
public Food[] newArray(int size) {
return new Food[size];
}
};
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(txtid);
dest.writeString(txtName);
dest.writeString(txtDesc);
dest.writeString(txtImage);
dest.writeByte((byte) (txtFav ? 1 : 0));
dest.writeString(items);
dest.writeInt(converted_image);
}
}
公共级食品工具可包裹{
受保护的int-txtid;
受保护字符串txtName;
受保护字符串txtDesc;
受保护的字符串txtImage;
受保护布尔txtFav;
受保护的字符串项目;
受保护的int转换图像;
public int getTxtid(){
返回txtid;
}
公共无效setTxtid(int-txtid){
this.txtid=txtid;
}
公共字符串getTxtName(){
返回txtName;
}
公共void setTxtName(字符串txtName){
this.txtName=txtName;
}
公共字符串getTxtDesc(){
返回txtDesc;
}
公共void setTxtDesc(字符串txtDesc){
this.txtDesc=txtDesc;
}
公共字符串getTxtImage(){
返回txtImage;
}
公共void setTxtImage(字符串txtImage){
this.txtImage=txtImage;
}
公共布尔值isTxtFav(){
返回txtFav;
}
公共无效设置txtFav(布尔值txtFav){
this.txtFav=txtFav;
}
公共字符串getItems(){
退货项目;
}
公共void集合项(字符串项){
这个项目=项目;
}
public int getu image(){
返回转换后的图像;
}
public void setConverted_image(int converted_image){
this.converted_image=转换的_image;
}
受保护食物({}
受保护食品(包裹内){
txtid=in.readInt();
txtName=in.readString();
txtDesc=in.readString();
txtImage=in.readString();
txtFav=in.readByte()!=0;
items=in.readString();
已转换的_image=in.readInt();
}
公共静态最终创建者=新创建者(){
@凌驾
公共食品包裹(包裹内){
归还新食物(在);
}
@凌驾
公共食品[]新数组(整数大小){
返回新食物[尺寸];
}
};
@凌驾
公共int描述内容(){
返回0;
}
@凌驾
公共无效写入包裹(包裹目的地,内部标志){
目的写入(txtid);
目的地书面记录(txtName);
目的地记录(txtDesc);
目的写入限制(txtImage);
目标写入字节((字节)(txtFav?1:0));
目的地书面资本(项目);
目标写入(转换的图像);
}
}
事实上,它没有运行任何错误,但主要问题是特定的数据库行没有更新。我从android设备监视器中找到它,发现数据库中的特定值没有更新。您得到了可读的数据库。你不能更新这个。尝试使用可写的。尝试以下代码:
public int addDBfav(int id)
{
SQLiteDatabase sqLiteDatabase;
DbHelper myDbHelper=new DbHelper(this);
try{
myDbHelper.createDatabase();
}catch (IOException e)
{
throw new Error("unable to create database");
}
myDbHelper.openDataBase();
sqLiteDatabase=myDbHelper.getWritableDatabase();
ContentValues contentValues=new ContentValues();
contentValues.put("fav",true);
int part= sqLiteDatabase.update("food",contentValues,"food_id = "+Integer.toString(id),null);
Log.i("success","successfuly done "+Integer.toString(part));
return part;
}
我做了,但没用。我仍然有同样的问题