【发布时间】：2018-10-14 20:42:39
【问题描述】：
在 dbhelper 类中创建数据库和其他东西
public class DBHandler extends SQLiteOpenHelper{
private static final String TAG =DBHandler.class.getSimpleName();
private static final int VERSION =1;
private static final String DATABASE_NAME = "userDb.db";
private String CREATE_TABLE ="CREATE TABLE " + Users.TABLE_NAME + "("
+ Users._ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + Users.USER_NAME + " TEXT,"
+ Users.USER_DOB + " TEXT," + Users.USER_GENDER + " TEXT," + Users.USER_PASSWORD + " TEXT " + ")";
private String DROP_TABLE ="DROP TABLE IF EXISTS " +Users.TABLE_NAME;
public DBHandler(Context context) {
super(context, DATABASE_NAME, null, VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL(DROP_TABLE);
onCreate(db);
}
将数据插入数据库sqlite
//adding users
public boolean addInfo(Users addUser){
boolean result = true;
try {
SQLiteDatabase db =this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(Users.USER_NAME,addUser.getUserName());
values.put(Users.USER_DOB,addUser.getDob());
values.put(Users.USER_GENDER,addUser.getGender());
values.put(Users.USER_PASSWORD,addUser.getPassword());
result =db.insert(Users.TABLE_NAME,null,values)>0;
}
catch (Exception ex){
result=false;
ex.getMessage();
}
return result;
}
数据库的更新方法。这样可以吗
//updateInfor()
public boolean updateInfor(Users updateUser){
boolean result = true;
try{
SQLiteDatabase db =this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(Users.USER_NAME,updateUser.getUserName());
values.put(Users.USER_DOB,updateUser.getDob());
values.put(Users.USER_GENDER,updateUser.getGender());
values.put(Users.USER_PASSWORD,updateUser.getPassword());
//update using user id
String[] hello ={String.valueOf(updateUser.getUserName())};
result =db.update(Users.TABLE_NAME,values,Users.USER_NAME+ "=? ",hello) >0;
}
catch (Exception ex){
result =false;
}
return result;
}
从数据库中检索所有数据`
//retrieve data from database
public List<Users>readAllInfor(){
String[] columns ={Users.USER_NAME,Users.USER_DOB,Users.USER_GENDER,Users.USER_PASSWORD};
List<Users> usersList = new ArrayList<Users>();
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(Users.TABLE_NAME,columns,null,null,null,null,null);
if(cursor.moveToFirst()){
do{
Users user = new Users();
user.setUserId(Integer.parseInt(cursor.getString(cursor.getColumnIndex(Users._ID))));
user.setUserName(cursor.getString(cursor.getColumnIndex(Users.USER_NAME)));
user.setDob(cursor.getString(cursor.getColumnIndex(Users.USER_DOB)));
user.setGender(cursor.getString(cursor.getColumnIndex(Users.USER_GENDER)));
user.setPassword(cursor.getString(cursor.getColumnIndex(Users.USER_PASSWORD)));
usersList.add(user);
}while (cursor.moveToNext());
}
cursor.close();
db.close();
return usersList;
}
使用自己的 id 从数据库中检索数据
//overloading method to retrive by id
public Cursor readAllInfor(String user){
SQLiteDatabase db = getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM "+UserProfile.Users.table_name+" WHERE "+UserProfile.Users.Column_UserName+" = '"+user+"'",null);
return cursor;
}
从数据库中删除用户
public boolean deleteUser(Users user){
SQLiteDatabase db = this.getWritableDatabase();
db.delete(Users.TABLE_NAME,Users._ID + "=?",
new String[]{String.valueOf(user.getUserId())});
db.close();
return true;
}
使用用户名和密码登录部分检查用户
public Users checkUser(String email,String password){
Users users =null;
try {
SQLiteDatabase db = getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM " + Users.TABLE_NAME + " WHERE userName = ? AND userPassword = ?" ,new String[]{email,password} );
if (cursor.moveToFirst()){
users = new Users();
users.setUserId(cursor.getInt(0));
users.setUserName(cursor.getString(1));
users.setDob(cursor.getString(2));
users.setGender(cursor.getString(3));
users.setPassword(cursor.getString(4));
}
}catch (Exception e){
users=null;
}
return users;
}
db helper 中所有方法的含义
public class ProfileManangment extends AppCompatActivity implements View.OnClickListener{
private final AppCompatActivity activity = ProfileManangment.this;
private RadioGroup groupGender;
private RadioButton radioButton;
private EditText username,password,dob;
private Button update;
private Users users;
private DBHandler dbHandler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_profile_manangment);
iniViews();
iniObjects();
iniListners();
}
private void iniViews() {
username =findViewById(R.id.regUsername);
password =findViewById(R.id.regPassword);
dob =findViewById(R.id.regDob);
update=findViewById(R.id.btnUpadateReg);
groupGender = findViewById(R.id.radioGroupGender);
}
private void iniObjects() {
users =new Users();
dbHandler =new DBHandler(activity);
}
private void iniListners() {
update.setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.btnUpadateReg : addtoDataBase();
break;
}
}
//get values of readio button
public void radioButtonValue(View v){
int radioId = groupGender.getCheckedRadioButtonId();
radioButton =findViewById(radioId);
}
private void addtoDataBase() {
users.setUserName(username.getText().toString().trim());
users.setDob(dob.getText().toString().trim());
int radioId = groupGender.getCheckedRadioButtonId();
radioButton =findViewById(radioId);
users.setGender(radioButton.getText().toString().trim());
users.setPassword(password.getText().toString().trim());
boolean result =dbHandler.addInfo(users);
if(result){
Toast.makeText(ProfileManangment.this,"SUCCESSFULLY REGISTERED",Toast.LENGTH_LONG).show();
Intent intentEditProfile = new Intent(ProfileManangment.this,EditProfile.class);
startActivity(intentEditProfile);
}
else
Toast.makeText(ProfileManangment.this,"AN ERROR OCCURRED",Toast.LENGTH_LONG).show();
}
}
搜索是最重要的事情。请告诉我任何人如何使用搜索。我的代码如下
/**
* StringBuffer was used in aid of using the AlertDialog.Builder to display all the stuff
* on the screen
*/
public void search(View view) {
User user = db.readAllInfor(ET_username.getText().toString());
if(user == null) {
showStuff("Error", "No Data Found!");
return;
}
StringBuffer buffer = new StringBuffer();
buffer.append("User ID: " + user.getId() + "\n");
buffer.append("Username: " + user.getUsername() + "\n");
buffer.append("Date Of Birth: " + user.getDateOfBirth() + "\n");
buffer.append("Password: " + user.getPassword() + "\n");
buffer.append("Gender: " + user.getGender() + "\n\n");
showStuff("Data", buffer.toString());
}
/**
* This was done in the aid of displaying the stuff on the screen
*/
public void showStuff(String title, String message) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setCancelable(true);
builder.setTitle(title);
builder.setMessage(message);
builder.show();
}
创建 getter 和 setter 以及表列的用户类
class Users implements BaseColumns{
public static final String TABLE_NAME = "user";
public static final String USER_NAME = "userName";
public static final String USER_PASSWORD = "userPassword";
public static final String USER_DOB = "dob";
public static final String USER_GENDER = "userGender";
private int userId;
private String userName;
private String Password;
private String dob;
private String gender;
public Users(){}
【问题讨论】：
标签： android-database