[英]SQLite not updating table
我正在学习数据库。 我创建了一个SQLite数据库。 我的布局中有6个EditText,单击“保存到数据库”按钮时,数据将保存到数据库。 当我单击“显示”按钮时,它将在EditTexts中显示数据库详细信息。 但是问题是,当我尝试将不同的数据保存在同一数据库中时,它不会使用新数据进行更新,并且“显示”按钮仅显示旧数据。
public class FragmentFour extends Fragment {
EditText name_ET, website_ET, bio_ET, altEmail_ET, phone_ET, facebook_ET;
String name_str="", website_str="", bio_str="", altEmail_str="", phone_str="", facebook_str="";
Button save, show, clear;
private SQLiteHandler db;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_four, container, false);
db = new SQLiteHandler(getActivity());
name_ET = (EditText)rootView.findViewById(R.id.name);
website_ET = (EditText)rootView.findViewById(R.id.webiste);
bio_ET = (EditText)rootView.findViewById(R.id.bio);
altEmail_ET = (EditText)rootView.findViewById(R.id.altEmail);
phone_ET = (EditText)rootView.findViewById(R.id.phone);
facebook_ET = (EditText)rootView.findViewById(R.id.facebook);
save = (Button)rootView.findViewById(R.id.btn_save);
show = (Button)rootView.findViewById(R.id.btn_show);
clear = (Button)rootView.findViewById(R.id.btn_clr);
save.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
name_str = name_ET.getText().toString();
website_str = website_ET.getText().toString();
bio_str = bio_ET.getText().toString();
altEmail_str = altEmail_ET.getText().toString();
phone_str = phone_ET.getText().toString();
facebook_str = facebook_ET.getText().toString();
db.addProfile(name_str, website_str, bio_str, altEmail_str, phone_str, facebook_str);
name_ET.setText("");
website_ET.setText("");
bio_ET.setText("");
altEmail_ET.setText("");
phone_ET.setText("");
facebook_ET.setText("");
}
});
show.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
HashMap<String, String> pro = db.getProfDetails();
String name = pro.get("name");
String website = pro.get("website");
String bio = pro.get("bio");
String email = pro.get("email");
String phone = pro.get("phone");
String facebook = pro.get("facebook");
name_ET.setText(name);
website_ET.setText(website);
bio_ET.setText(bio);
altEmail_ET.setText(email);
phone_ET.setText(phone);
facebook_ET.setText(facebook);
}
});
clear.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
name_ET.setText("");
website_ET.setText("");
bio_ET.setText("");
altEmail_ET.setText("");
phone_ET.setText("");
facebook_ET.setText("");
}
});
return rootView;
}
}
SQLite数据库
public class SQLiteHandler extends SQLiteOpenHelper {
private static final String TAG = SQLiteHandler.class.getSimpleName();
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "android_api";
// Profile Settings table name
private static final String TABLE_PROF = "prof";
// Profile Settings information names
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_WEBSITE = "website";
private static final String KEY_BIO = "bio";
private static final String KEY_ALT_EMAIL = "alt_email";
private static final String KEY_PHONE = "phone";
private static final String KEY_FACEBOOK = "facebook";
public SQLiteHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_PROF_TABLE = "CREATE TABLE " + TABLE_PROF + "("+KEY_ID+" INTEGER PRIMARY KEY, "+KEY_NAME+" TEXT, "+KEY_WEBSITE+" TEXT, "+KEY_BIO+" TEXT, "+KEY_ALT_EMAIL+" TEXT, "+KEY_PHONE+" TEXT, "+KEY_FACEBOOK+" TEXT" + ")";
db.execSQL(CREATE_PROF_TABLE);
Log.d(TAG, "Database tables created");
}
// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_PROF);
// Create tables again
onCreate(db);
}
/**
* Storing Prof_settings details in database
* */
public void addProfile(String name, String website, String bio, String alt_email, String phone, String facebook){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, name);
values.put(KEY_WEBSITE, website);
values.put(KEY_BIO, bio);
values.put(KEY_ALT_EMAIL, alt_email);
values.put(KEY_PHONE, phone);
values.put(KEY_FACEBOOK, facebook);
// Inserting Row
long id = db.insert(TABLE_PROF, null, values);
db.close(); // Closing database connection
Log.d(TAG, "New profile settings inserted into sqlite: " + id);
}
/**
* Getting Profile Settings data from database
* */
public HashMap<String, String> getProfDetails() {
HashMap<String, String> pro = new HashMap<String, String>();
String selectQuery = "SELECT * FROM " + TABLE_PROF;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// Move to first row
cursor.moveToFirst();
if (cursor.getCount() > 0) {
pro.put("name", cursor.getString(1));
pro.put("website", cursor.getString(2));
pro.put("bio", cursor.getString(3));
pro.put("email", cursor.getString(4));
pro.put("phone", cursor.getString(5));
pro.put("facebook", cursor.getString(6));
}
cursor.close();
db.close();
// return log details
Log.d(TAG, "Fetching profile details from Sqlite: " + pro.toString());
return pro;
}
/**
* Re crate database Delete all tables and create them again
* */
public void deleteUsers() {
SQLiteDatabase db = this.getWritableDatabase();
// Delete All Rows
db.delete(TABLE_PROF, null, null);
db.close();
Log.d(TAG, "Deleted all profile info from sqlite");
}
}
场景1
我认为数据正在保存到数据库中,但是问题是,单击“保存到数据库”按钮时,您正在将数据插入到表中。
当您检索数据时,将从光标获得第一行( cursor.moveToFirst();
)并将其显示在EditText
。
如果表中已经存在数据,则应该更新该值,而不是将值插入数据库中,或者在插入新值之前先删除现有行。
如果要清除表
只需添加此行
db.execSQL("delete from "+ TABLE_PROF);
之前
long id = db.insert(TABLE_PROF, null, values);
在addProfile()
方法中
如果要更新现有行
使用这样的命令
db.update(TABLE_PROF, values, "_id=1", null);
但是请检查是否存在现有项目。 如果项目不存在,则插入行/
方案2
或者,如果要添加多行,则应在游标的最后一行( cursor.moveToLast();
)中的EditText
显示值。
更改
cursor.moveToFirst();
至
cursor.moveToLast();
然后您将看到更新的值。
在单击按钮时,您总是将新行插入数据库,代码中没有更新语句。
同样,当您查询数据库并找回游标时,该游标可用于遍历结果。 您在那里所做的基本上是指示光标移至MoveToFirst,而您仅查询第一行。 因此,即使添加了更新功能,您也将始终获得结果的第一行。
查看官方文档,以了解如何更新行以及如何使用游标。
见这是一个例子。
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