第二阶段冲刺10

1、我昨天的成就：完成了登录功能的连接数据库功能
2、遇到什么困难：在判断查询到数据库中有无已注册的数据遇到困难
3、今天的任务：完善登录注册功能

package com.example.lenovo.share;

import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;


public class LoginActivity extends AppCompatActivity {


    private Button login;
    private Button register;
    //申明控件
    private EditText edit_username;
    private EditText edit_password;
    //申明参数
    String username;
    String password;
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        //调用init方法
        init();
    }

    private void init() {
        //获取相应控件
        edit_username=findViewById(R.id.login_user);
        edit_password=findViewById(R.id.login_password);
        login=findViewById(R.id.login_login);
        register=findViewById(R.id.login_register);
        //创建login点击事件
        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //获取相应值
                username=edit_username.getText().toString().trim();
                password=edit_password.getText().toString().trim();
                Toast.makeText(LoginActivity.this, "账号："+username+"密码："+password, Toast.LENGTH_SHORT).show();
                //判断输入内容
                if(TextUtils.isEmpty(username)){
                    Toast.makeText(LoginActivity.this, "请输入用户名", Toast.LENGTH_SHORT).show();
                    return;
                }else if(TextUtils.isEmpty(password)){
                    Toast.makeText(LoginActivity.this, "请输入密码", Toast.LENGTH_SHORT).show();
                    return;
                }else if(notExitUserAndPsd(username,password)){
                    Toast.makeText(getApplicationContext(),"账号或密码错误！",Toast.LENGTH_SHORT).show();
                    return;
                }else{
                    Intent intent=new Intent(LoginActivity.this,MainActivity.class);
                    Toast.makeText(getApplicationContext(),"登陆成功！",Toast.LENGTH_SHORT).show();
                    startActivity(intent);
                    LoginActivity.this.finish();
                }
            }
        });

        //创建注册点击事件
        register.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent=new Intent(LoginActivity.this,RegisterActivity.class);
                startActivity(intent);
            }
        });
    }

    //方法：查询数据库中的账号，密码
    private boolean notExitUserAndPsd(String username, String password) {
       // Toast.makeText(getApplicationContext(),"在query！",Toast.LENGTH_SHORT).show();
        DbHelper helper = new DbHelper(this,"share.db",null,1);
        SQLiteDatabase db = helper.getWritableDatabase();

        //查询数据库所有的数据
        Cursor c = db.query("user",null,"username=? and password=?",new String[]{username,password},null,null,null);
        //Toast.makeText(getApplicationContext(),c.getString(c.getColumnIndex("username")),Toast.LENGTH_SHORT).show();
        //boolean类型的b用于判断是否查询到，true表示没找到，false表示找到了
        boolean b = true;
        if(c!=null&&c.getCount()>=1)
        {
            Toast.makeText(getApplicationContext(),"姓名",Toast.LENGTH_SHORT).show();
           // Toast.makeText(getApplicationContext(),"姓名"+c.getString(c.getColumnIndex("username")),Toast.LENGTH_SHORT).show();
            b=false;
            this.finish();
        }
        return b;

    }



}