我现在正在学习数据库。我创建了一个SQLite数据库。我的布局中有6个EditText，当我点击＆＃34;保存到DB＆＃34;按钮将数据保存到DB。当我点击＆＃34; Show＆＃34;按钮，它在EditTexts中显示数据库详细信息。但问题是，当我尝试在同一个数据库中保存不同的数据时，它不会使用新数据和＆＃34;显示＆＃34;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");
}
}
答案 0 :(得分：2)
情景1
我认为数据正在保存到数据库，但问题是点击＆＃34;保存到数据库＆＃34;按钮，您将数据插入表中。
检索数据时，您会从光标（cursor.moveToFirst();）获取第一行并将其显示在EditText中。
如果数据已存在于表中，或者只是在插入新行之前删除现有行，而不是将值插入数据库，则应更新它。
如果您想清除表格
只需添加此行
即可db.execSQL("delete from "+ TABLE_PROF);
之前
long id = db.insert(TABLE_PROF, null, values);
addProfile()方法中的
如果您想更新现有行
使用这样的命令
db.update(TABLE_PROF, values, "_id=1", null);
但请检查是否有现有物品。如果项目不存在，只需插入行/
场景2
或者，如果要添加多行，则应在光标的最后一行（EditText）的cursor.moveToLast();中显示值。
更改
cursor.moveToFirst();
到
cursor.moveToLast();
然后您将看到更新的值。
答案 1 :(得分：0)
单击该按钮，您总是在数据库中插入一个新行，代码中没有更新语句。
此外，当您查询数据库并获得光标时，该光标可用于迭代结果。你在那里做的基本上是指示光标moveToFirst而你只查询第一行。因此，即使您添加更新功能，您也将始终获得结果的第一行。
查看官方文档，了解如何更新行以及如何使用游标。
有关示例，请参阅this。