每日总结 3.2
今天学习了注册界面和数据库的链接。
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:background="@color/grey7d"> <LinearLayout android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="wrap_content"> <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:text="用户名（学号）：" android:layout_marginTop="30dp" android:textSize="25sp" android:textColor="#000000" android:layout_weight="1"/> <EditText android:id="@+id/userName" android:layout_width="0dp" android:layout_height="wrap_content" android:hint="请输入用户名" android:layout_marginTop="30dp" android:textSize="20sp" android:textColor="#2196F3" android:layout_weight="2"/> </LinearLayout> <LinearLayout android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="wrap_content"> <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:text="密码：" android:textSize="25sp" android:layout_marginTop="30dp" android:textColor="#000000" android:layout_weight="1"/> <EditText android:id="@+id/userpassword" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_marginTop="30dp" android:hint="请输入密码" android:textSize="20sp" android:textColor="#2196F3" android:layout_weight="2" android:inputType="textWebPassword"/> </LinearLayout> <LinearLayout android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="wrap_content"> <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:text="姓名：" android:layout_marginTop="30dp" android:textSize="25sp" android:textColor="#000000" android:layout_weight="1"/> <EditText android:id="@+id/userNames" android:layout_width="0dp" android:layout_height="wrap_content" android:hint="请输入姓名" android:layout_marginTop="30dp" android:textSize="20sp" android:textColor="#2196F3" android:layout_weight="2"/> </LinearLayout> <LinearLayout android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="wrap_content"> <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:text="手机号：" android:layout_marginTop="30dp" android:textSize="25sp" android:textColor="#000000" android:layout_weight="1"/> <EditText android:id="@+id/usertel" android:layout_width="0dp" android:layout_height="wrap_content" android:hint="请输入手机号" android:layout_marginTop="30dp" android:textSize="20sp" android:textColor="#2196F3" android:layout_weight="2"/> </LinearLayout> <LinearLayout android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="wrap_content"> <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:text="班级：" android:layout_marginTop="30dp" android:textSize="25sp" android:textColor="#000000" android:layout_weight="1"/> <EditText android:id="@+id/userclass" android:layout_width="0dp" android:layout_height="wrap_content" android:hint="请输入班级" android:layout_marginTop="30dp" android:textSize="20sp" android:textColor="#2196F3" android:layout_weight="2"/> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <Button android:textColor="#000000" android:layout_marginTop="40dp" android:layout_marginLeft="30dp" android:layout_marginRight="30dp" android:textSize="25sp" android:textAllCaps="false" android:text="确认" android:id="@+id/reday" android:layout_width="match_parent" android:layout_height="wrap_content"/> <Button android:textColor="#000000" android:layout_marginTop="20dp" android:layout_marginLeft="30dp" android:layout_marginRight="30dp" android:textSize="25sp" android:textAllCaps="false" android:text="取消" android:id="@+id/back" android:layout_width="match_parent" android:layout_height="wrap_content"/> </LinearLayout> </LinearLayout>
package com.example.clock; import static com.example.clock.R.id.userNames; import androidx.appcompat.app.AppCompatActivity; import android.annotation.SuppressLint; import android.os.Bundle; import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.os.Bundle; import android.text.TextUtils; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; import com.example.clock.db.DatabaseHelper; import com.example.clock.jiben.User; import com.example.clock.jiben.User; import java.util.ArrayList; public class Register extends AppCompatActivity { private DatabaseHelper mSQLite; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_register); //找到各个控件 Button btn_ready = findViewById(R.id.reday); Button btn_back = findViewById(R.id.back); EditText ed_name = findViewById(R.id.userName); EditText ed_password = findViewById(R.id.userpassword); EditText ed_name1 = findViewById(R.id.userNames); EditText ed_tel= findViewById(R.id.usertel); EditText ed_class = findViewById(R.id.userclass); //注册监听事件 btn_ready.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { //获取输入的用户名和密码 String name = ed_name.getText().toString().trim(); String password = ed_password.getText().toString().trim(); String name1 =ed_name1.getText().toString().trim(); String tel = ed_tel.getText().toString().trim(); String classs=ed_class.getText().toString().trim(); //获取数据库数据，判断用户名是否已存在 ArrayList<User> data = mSQLite.getAllDATA(); boolean flag = false; for(int i = 0; i < data.size(); i++){ User userdata = data.get(i); if(name.equals(userdata.getName())){ flag = true; break; }else{ flag = false; } } //判断用户名和密码是否为空 if(!TextUtils.isEmpty(name)&&!TextUtils.isEmpty(password)){ if(!flag){ mSQLite.insert(name, password,name1,tel,classs); Intent intent1 = new Intent(Register.this, Login.class); startActivity(intent1); finish(); Toast.makeText(Register.this, "注册成功", Toast.LENGTH_SHORT).show(); } else{ Toast.makeText(Register.this, "用户名已被注册", Toast.LENGTH_SHORT).show(); } } else{ Toast.makeText(Register.this, "用户名与密码不能为空", Toast.LENGTH_SHORT).show(); } } }); //监听返回按钮 btn_back.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Intent intent2 = new Intent(Register.this, Login.class); startActivity(intent2); finish(); } }); mSQLite = new DatabaseHelper(Register.this); } }
package com.example.clock.db; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import androidx.annotation.Nullable; import com.example.clock.jiben.User; import com.example.clock.jiben.User; import java.util.ArrayList; import java.util.jar.Attributes; import javax.xml.namespace.NamespaceContext; public class DatabaseHelper extends SQLiteOpenHelper { //创建一个数据库 private SQLiteDatabase db; public DatabaseHelper(@Nullable Context context) { super(context, "db_test", null, 1); db = getReadableDatabase(); } @Override public void onCreate(SQLiteDatabase db) { //在第一次创建数据库的时候，创建一些字段 String sql = "create table user(_id integer, name varchar(50), password varchar(40),names varchar(20),tel varchar(20),class varchar(20))"; db.execSQL(sql);//sql语句的执行函数 } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { //如果这个表中存在user,我们可以先把他去掉,然后重新创建 String sql = "DROP TABLE IF EXISTS user"; db.execSQL(sql); onCreate(db); } //为使项目结构更加紧凑，我们在此类中编写增删改查的函数,因为只有登录和注册界面,因此只涉及到写入数据库insert和query的操作 public void insert(String name,String password ,String namele,String tel,String classs){ db.execSQL("insert into user(name,password,names,tel,class)VALUES(?,?,?,?,?)",new Object[]{name,password,namele,tel,classs}); } public ArrayList<User> getAllDATA(){//查询数据库 ArrayList<User> list = new ArrayList<User>(); //查询数据库中的数据,并将这些数据按照降序的情况排列 Cursor cursor = db.query("user",null,null,null,null,null,"name DESC"); while(cursor.moveToNext()){ int index_name = cursor.getColumnIndex("name"); int index_password = cursor.getColumnIndex("password"); int index_names = cursor.getColumnIndex("names"); int index_tel = cursor.getColumnIndex("tel"); int index_classs=cursor.getColumnIndex("class"); String name = cursor.getString(index_name); String password = cursor.getString(index_password); String names = cursor.getString(index_names); String tel = cursor.getString(index_tel); String classs = cursor.getString(index_classs); list.add(new User(name,password,names,tel,classs)); } return list; } }
