手机直播源码，一个简单的Android登录实现

一、实体类

User

<br>package com.example.login.model;<br> <br>public class User {<br>    public String account;<br>    public String loginKey;<br>    public String mail;<br> <br>    public User() {<br>    }<br>    public User(String account, String loginKey, String mail) {<br>        this.account = account;<br>        this.loginKey = loginKey;<br>        this.mail = mail;<br>    }<br>    public String getAccount() {<br>        return account;<br>    }<br> <br>    public void setAccount(String account) {<br>        this.account = account;<br>    }<br> <br>    public String getLoginKey() {<br>        return loginKey;<br>    }<br> <br>    public void setLoginKey(String loginKey) {<br>        this.loginKey = loginKey;<br>    }<br> <br>    public String getMail() {<br>        return mail;<br>    }<br> <br>    public void setMail(String mail) {<br>        this.mail = mail;<br>    }<br> <br>    @Override<br>    public String toString() {<br>        return "User{" +<br>                "account='" + account + '\'' +<br>                ", loginKey='" + loginKey + '\'' +<br>                ", mail='" + mail + '\'' +<br>                '}';<br>    }<br>}

二、数据库操作类

MySQLiteOpenHelper<br>package com.example.login;<br> <br>import android.content.Context;<br>import android.database.Cursor;<br>import android.database.sqlite.SQLiteDatabase;<br>import android.database.sqlite.SQLiteOpenHelper;<br>import androidx.annotation.Nullable;<br> <br>public class MySQLiteOpenHelper extends SQLiteOpenHelper {<br> <br>    private SQLiteDatabase db; //声明一个数据库变量db<br>    private static final String DB_NAME="mySQLite.db";<br>    private static final String TABLE_NAME="user";<br> <br>//    public MySQLiteOpenHelper(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory, int version) {<br>//        super(context, name, factory, version);<br> <br>    //简化后，仅需传入contex（上下文）一个参数即可创建MySQLiteOpenHelper对象<br>      public MySQLiteOpenHelper(@Nullable Context context) {<br>           super(context, DB_NAME, null, 1);<br>           db=getReadableDatabase();<br>       }<br> <br>    @Override<br>    public void onCreate(SQLiteDatabase db) {<br>          //创建数据库SQL语句<br>          String CREATE_TABLE_SQL= "create table "+TABLE_NAME+" (id Integer primary key autoincrement,account text,login_key text,mail text)";<br>          //创建数据库表<br>          db.execSQL(CREATE_TABLE_SQL);<br>    }<br> <br>    @Override<br>    public void onUpgrade(SQLiteDatabase db, int i, int i1) {<br>       //更新需做的操作<br>        db.execSQL("drop table if exists "+TABLE_NAME);<br>        onCreate(db);<br>    }<br> <br>    //插入用户<br>    public void insert(String account,String loginKey,String mail){<br>        String INSERT_USER_SQL="insert into "+TABLE_NAME+" (account,login_key,mail) values(?,?,?)";<br>        db.execSQL(INSERT_USER_SQL,new Object[]{account,loginKey,mail});<br>    }<br> <br>    //根据账号查找密码<br>    public String queryKeyByAcount(String account){<br>          String QUERY_KEY_BYACOUNT_SQL="select login_key from "+TABLE_NAME+" where account=?";<br>          //rawQuery()⽅法的第⼀个参数为select语句；第⼆个参数为select语句中占位符参数的值，如果select语句没有使⽤占位符，该参数可以设置为null。<br>          Cursor cursor=db.rawQuery(QUERY_KEY_BYACOUNT_SQL,new String[]{account});<br>          //因为账号是唯一的，所以查找的结果有且只有一条，直接将游标的指向为first即可<br>          cursor.moveToFirst();<br>          String loginKey=cursor.getString(0);<br>          //关闭游标<br>          cursor.close();<br>          return loginKey;<br>    }<br> <br>    //在数据库中查找账号是否已经存在<br>    public Integer queryCountByAccount(String account){<br>          Cursor cursor=db.rawQuery("select count(*) from "+TABLE_NAME+" where account=?",new String[]{account});<br>          cursor.moveToFirst();<br>          int count=cursor.getInt(0);<br>          cursor.close();<br>          return count;<br>    }<br> <br>}