每日总结2023/3/1

今天学习了Android Studio

对于昨日的错误找到了对应的解决方案

没有在前面设置时间监听器，所以无法触发R.id事件

 

今日学习了链接本地数据库，

成果

 

 

 对于图一，代码如下

xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#f3f3f3"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="180dp"
        android:text="@string/app_name"
        android:textColor="@color/black"
        android:textSize="20dp"
        android:textStyle="bold" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="100dp"
        android:padding="20dp"
        android:orientation="vertical">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@drawable/ic_main_background"
            android:padding="5dp">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="用户名 : "
                android:textColor="@color/black"
                android:textSize="18dp" />

            <EditText
                android:id="@+id/main_ed_zhang"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:imeOptions="actionSearch"
                android:maxLength="10"
                android:hint="请输入用户名/ID"
                android:maxLines="1"
                android:singleLine="true" />
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:background="@drawable/ic_main_background"
            android:padding="5dp">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="密    码 : "
                android:textColor="@color/black"
                android:textSize="18dp" />

            <EditText
                android:id="@+id/main_ed_password"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:imeOptions="actionSearch"
                android:inputType="textPassword"
                android:maxLength="10"
                android:hint="请输入密码"
                android:maxLines="1"
                android:singleLine="true"
                android:textColorHint="#bcbcbc" />
        </LinearLayout>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:padding="5dp">

        <Button
            android:id="@+id/main_bu_deng"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="登录"
            android:onClick="onClick"
            android:textStyle="bold" />

        <Button
            android:id="@+id/main_bu_zhu"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:layout_weight="1"
            android:text="注册"
            android:onClick="onClick"
            android:textStyle="bold" />
    </LinearLayout>

</LinearLayout>

Java文件

package com.example.meiri;

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.Toast;

import com.example.meiri.db.DBOpenHelper;
import com.example.meiri.db.User;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    private DBOpenHelper mDBOpenHelper;
    private EditText mEtRegisteractivityzhang;
    private EditText mEtRegisteractivitypassword;
    private Button mBtRegisteractivitydeng;
    private Button mBtRegisteractivityzhu;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mDBOpenHelper = new DBOpenHelper(this);
    }
    private void initView() {
        // 初始化控件
        mEtRegisteractivityzhang = findViewById(R.id.main_ed_zhang);
        mEtRegisteractivitypassword = findViewById(R.id.main_ed_password);
        mBtRegisteractivitydeng = findViewById(R.id.main_bu_deng);
        mBtRegisteractivityzhu = findViewById(R.id.main_bu_zhu);

        // 设置点击事件监听器
        mBtRegisteractivitydeng.setOnClickListener(this::onClick);
        mBtRegisteractivityzhu.setOnClickListener(this::onClick);

    }

    public void onClick(View view) {
        switch (view.getId()) {
            // 跳转到注册界面
            case R.id.main_bu_zhu:
                startActivity(new Intent(this, RegisterActivity.class));
                finish();
                break;

            case R.id.main_bu_deng:
                String id = mEtRegisteractivityzhang.getText().toString().trim();
                String password = mEtRegisteractivitypassword.getText().toString().trim();

                if (!TextUtils.isEmpty(id) && !TextUtils.isEmpty(password)) {
                        ArrayList<User> data = mDBOpenHelper.getAllData();
                        boolean match = false;
                        for (int i = 0; i < data.size(); i++) {
                            User user = data.get(i);
                            if (id.equals(user.getName()) && password.equals(user.getPassword())/*&&phoneCode.equals(realCode)*/) {
                                match = true;
                                break;
                            } else {
                                match = false;
                            }
                        }

                        if (match) {
                            Toast.makeText(this, "登录成功", Toast.LENGTH_SHORT).show();
                            Intent intent = new Intent(this,DakaActivity.class);
                            startActivity(intent);
                            finish();//销毁此Activity
                        } else {
                            Toast.makeText(this, "用户名或密码不正确，请重新输入", Toast.LENGTH_SHORT).show();
                        }
                } else {
                    Toast.makeText(this, "请输入你的用户名或密码", Toast.LENGTH_SHORT).show();
                }


                break;
        }


    }
}

 

对于图二，代码如下；

xml文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#f3f3f3"
    android:orientation="vertical"
    tools:context=".RegisterActivity">

    <ImageView
        android:id="@+id/iv_registeractivity_back"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_marginLeft="10dp"
        android:src="@mipmap/back"
        android:layout_marginTop="15dp"
        android:clickable="true"
        android:onClick="onClick" />
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="注册"
        android:gravity="center"
        android:textStyle="bold"
        android:textSize="30dp"
        android:textColor="@color/black"
        android:layout_marginTop="20dp"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="100dp"
        android:orientation="vertical">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="18dp"
            android:layout_marginRight="18dp"
            android:background="@drawable/ic_main_background"
            android:gravity="center"
            android:orientation="vertical"
            android:paddingLeft="43dp"
            android:paddingRight="31dp">


            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="10dp"
                android:gravity="center_vertical"
                android:orientation="horizontal">

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="学号"
                    android:textSize="16dp" />

                <EditText
                    android:id="@+id/et_registeractivity_id"
                    android:layout_width="wrap_content"
                    android:layout_height="match_parent"
                    android:layout_marginLeft="20dp"
                    android:background="@null"
                    android:maxLength="8"
                    android:maxLines="1"
                    android:imeOptions="actionSearch"
                    android:singleLine="true"
                    android:hint="请输入学号"
                    android:textColor="#000000"
                    android:textColorHint="#bcbcbc"
                    android:textSize="18sp" />
            </LinearLayout>

            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginTop="23dp"
                android:layout_marginBottom="23dp"
                android:background="#f3f3f3" />

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:orientation="horizontal">

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="用户名"
                    android:textSize="16dp" />

                <EditText
                    android:id="@+id/et_registeractivity_username"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="20dp"
                    android:background="@null"
                    android:hint="请输入用户名/姓名"
                    android:textColor="@color/black"
                    android:imeOptions="actionSearch"
                    android:singleLine="true"
                    android:textColorHint="#bcbcbc"
                    android:textSize="18sp" />
            </LinearLayout>

            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginTop="23dp"
                android:layout_marginBottom="23dp"
                android:background="#f3f3f3" />
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:orientation="horizontal">

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="手机号"
                    android:textSize="16dp"/>

                <EditText
                    android:id="@+id/et_registeractivity_phone"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="20dp"
                    android:background="@null"
                    android:imeOptions="actionSearch"
                    android:singleLine="true"
                    android:hint="请输入手机号码"
                    android:textColor="@color/black"
                    android:textColorHint="#bcbcbc"
                    android:textSize="18sp"
                    tools:ignore="TextFields" />
            </LinearLayout>

            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginTop="23dp"
                android:layout_marginBottom="23dp"
                android:background="#f3f3f3" />

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:orientation="horizontal">

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/classes"
                    android:textSize="16dp"/>

                <EditText
                    android:id="@+id/et_registeractivity_classes"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="20dp"
                    android:background="@null"
                    android:imeOptions="actionSearch"
                    android:singleLine="true"
                    android:hint="请输入所在班级"
                    android:textColor="@color/black"
                    android:textColorHint="#bcbcbc"
                    android:textSize="18sp" />
            </LinearLayout>

            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginTop="23dp"
                android:layout_marginBottom="23dp"
                android:background="#f3f3f3" />
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:orientation="horizontal">

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="密码"
                    android:textSize="16dp"/>

                <EditText
                    android:id="@+id/et_registeractivity_password"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="20dp"
                    android:background="@null"
                    android:hint="请输入密码"
                    android:imeOptions="actionSearch"
                    android:singleLine="true"
                    android:inputType="textPassword"
                    android:textColor="@color/black"
                    android:textColorHint="#bcbcbc"
                    android:textSize="18sp" />
            </LinearLayout>

            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginTop="23dp"
                android:layout_marginBottom="23dp"
                android:background="#f3f3f3" />

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="10dp"
                android:layout_marginRight="15dp"
                android:orientation="horizontal">
                
                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:orientation="horizontal">

                    <EditText
                        android:id="@+id/et_registeractivity_phoneCodes"
                        android:layout_width="196dp"
                        android:layout_height="50dp"
                        android:layout_marginLeft="10dp"
                        android:layout_marginRight="10dp"
                        android:layout_weight="3"
                        android:hint="请输入验证码"
                        android:textColor="#000000"
                        android:textColorHint="#bcbcbc" />

                    <ImageView
                        android:id="@+id/iv_registeractivity_showCode"
                        android:layout_width="95dp"
                        android:layout_height="63dp"
                        android:layout_marginTop="-10dp"
                        android:layout_weight="1.5"
                        android:clickable="true"
                        android:onClick="onClick" />
                </LinearLayout>
            </LinearLayout>
        </LinearLayout>

        <Button
            android:id="@+id/bt_registeractivity_register"
            android:layout_width="match_parent"
            android:layout_height="55dp"
            android:layout_marginLeft="18dp"
            android:layout_marginTop="40dp"
            android:layout_marginRight="18dp"
            android:text="注册"
            android:textColor="@color/white"
            android:textSize="24sp" />
    </LinearLayout>

</RelativeLayout>

 

Java文件

package com.example.meiri;

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.ImageView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;
import com.example.meiri.db.DBOpenHelper;
import com.example.meiri.util.Code;

public class RegisterActivity extends AppCompatActivity implements View.OnClickListener {

    private String realCode;
    private DBOpenHelper mDBOpenHelper;
    private EditText mEtRegisteractivityID; //ID、学号
    private Button mBtRegisteractivityRegister;//注册
    private ImageView mIvRegisteractivityBack;//返回
    private EditText mEtRegisteractivityUsername;   //姓名
    private EditText mEtRegisteractivityPhone;  //手机号
    private EditText mEtRegisteractivityclasses;    //班级
    private EditText mEtRegisteractivitypassword;   //密码
    private EditText mEtRegisteractivityPhonecodes;//用户输入的验证码
    private ImageView mIvRegisteractivityShowcode;  //验证码图片

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);

        initView();

        mDBOpenHelper = new DBOpenHelper(this);

        //将验证码用图片的形式显示出来
        mIvRegisteractivityShowcode.setImageBitmap(Code.getInstance().createBitmap());
        realCode = Code.getInstance().getCode().toLowerCase();
    }

    private void initView() {
        mEtRegisteractivityID = findViewById(R.id.et_registeractivity_id);
        mEtRegisteractivityPhone = findViewById(R.id.et_registeractivity_phone);
        mEtRegisteractivityclasses = findViewById(R.id.et_registeractivity_classes);
        mBtRegisteractivityRegister = findViewById(R.id.bt_registeractivity_register);
        mIvRegisteractivityBack = findViewById(R.id.iv_registeractivity_back);
        mEtRegisteractivityUsername = findViewById(R.id.et_registeractivity_username);
        mEtRegisteractivityPhonecodes = findViewById(R.id.et_registeractivity_phoneCodes);
        mEtRegisteractivitypassword = findViewById(R.id.et_registeractivity_password);
        mIvRegisteractivityShowcode = findViewById(R.id.iv_registeractivity_showCode);


        mIvRegisteractivityBack.setOnClickListener(this);
        mIvRegisteractivityShowcode.setOnClickListener(this);
        mBtRegisteractivityRegister.setOnClickListener(this);
    }

    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.iv_registeractivity_back: //返回登录页面
                Intent intent1 = new Intent(this, MainActivity.class);
                startActivity(intent1);
                finish();
                break;
            case R.id.iv_registeractivity_showCode:    //改变随机验证码的生成
                mIvRegisteractivityShowcode.setImageBitmap(Code.getInstance().createBitmap());
                realCode = Code.getInstance().getCode().toLowerCase();
                break;
//            private String ID;      //用户ID（学号）
//            private String name;       //用户名，姓名
//            private String phone;      //手机号码
//            private String classes;  //用户单位，班级
//            private String password;    //  用户密码
            case R.id.bt_registeractivity_register:    //注册按钮
                //获取用户输入的用户名、密码、验证码
                String ID = mEtRegisteractivityID.getText().toString().trim();
                String username = mEtRegisteractivityUsername.getText().toString().trim();
                String phone = mEtRegisteractivityPhone.getText().toString().trim();
                String classes = mEtRegisteractivityclasses.getText().toString().trim();
                String password = mEtRegisteractivitypassword.getText().toString().trim();
                String phoneCode = mEtRegisteractivityPhonecodes.getText().toString().toLowerCase();
                //注册验证
                if (!TextUtils.isEmpty(ID) && !TextUtils.isEmpty(username)
                        && !TextUtils.isEmpty(phone) && !TextUtils.isEmpty(classes)
                        && !TextUtils.isEmpty(password) && !TextUtils.isEmpty(phoneCode)) {
                    if (phoneCode.equals(realCode)) {
                        //将用户名和密码加入到数据库中
                        mDBOpenHelper.add(ID,username, phone,classes,password);
                        Intent intent2 = new Intent(this, MainActivity.class);
                        startActivity(intent2);
                        finish();
                        Toast.makeText(this, "验证通过，注册成功", Toast.LENGTH_SHORT).show();
                    } else {
                        Toast.makeText(this, "验证码错误,注册失败", Toast.LENGTH_SHORT).show();
                    }
                } else {
                    Toast.makeText(this, "未完善信息，注册失败", Toast.LENGTH_SHORT).show();
                }
                break;
        }
    }
}

 今日新问题：

Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null

尝试在null对象上调用虚方法'android.text.Editable android.widget.EditText.getText()'