2022-10-29学习内容

1.记住密码

1.1LoginMainActivity.java

package com.example.chapter06;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

import androidx.activity.result.ActivityResult;
import androidx.activity.result.ActivityResultCallback;
import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

import com.example.chapter06.util.ViewUnil;

import java.util.Random;

public class LoginMainActivity extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener, View.OnClickListener {

    private TextView tv_password;
    private EditText et_password;
    private Button btn_forget;
    private CheckBox ck_remember;
    private EditText et_phone;
    private RadioButton rb_verifycode;
    private RadioButton rb_password;
    private ActivityResultLauncher<Intent> register;
    private Button btn_login;
    private String mPassword = "111111";
    private String mVerifyCode;
    private SharedPreferences preferences;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login_main);
        RadioGroup rg_login = findViewById(R.id.rg_login);
        tv_password = findViewById(R.id.tv_password);
        et_phone = findViewById(R.id.et_phone);
        et_password = findViewById(R.id.et_password);
        btn_forget = findViewById(R.id.btn_forget);
        ck_remember = findViewById(R.id.ck_remember);
        rb_password = findViewById(R.id.rb_password);
        rb_verifycode = findViewById(R.id.rb_verifycode);
        btn_login = findViewById(R.id.btn_login);
        // 给rg_login设置单选监听器
        rg_login.setOnCheckedChangeListener(this);
        // 给et_phone添加文本变更监听器
        et_phone.addTextChangedListener(new HideTextWatcher(et_phone, 11));
        // 给et_password添加文本变更监听器
        et_password.addTextChangedListener(new HideTextWatcher(et_password, 6));
        btn_forget.setOnClickListener(this);
        btn_login.setOnClickListener(this);

        register = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), new ActivityResultCallback<ActivityResult>() {
            @Override
            public void onActivityResult(ActivityResult result) {
                Intent intent = result.getData();
                if (intent != null && result.getResultCode() == Activity.RESULT_OK) {
                    // 用户密码已改为新密码，故更新密码变量
                    mPassword = intent.getStringExtra("new_password");
                }
            }
        });

        preferences = getSharedPreferences("config", Context.MODE_PRIVATE);
        reload();
    }

    private void reload() {
        boolean isRember = preferences.getBoolean("isRember", false);
        if (isRember) {
            String phone = preferences.getString("phone", "");
            et_phone.setText(phone);
            String password = preferences.getString("password", "");
            et_password.setText(password);
            ck_remember.setChecked(true);
        }
    }

    @Override
    public void onCheckedChanged(RadioGroup group, int checkedId) {
        switch (checkedId) {
            // 选择了密码登录
            case R.id.rb_password:
                tv_password.setText(getString(R.string.login_password));
                et_password.setHint(getString(R.string.input_password));
                btn_forget.setText(getString(R.string.forget_password));
                ck_remember.setVisibility(View.VISIBLE);
                break;
            // 选择了验证码登录
            case R.id.rb_verifycode:
                tv_password.setText(getString(R.string.verifycode));
                et_password.setHint(getString(R.string.input_verifycode));
                btn_forget.setText(getString(R.string.get_verifycode));
                ck_remember.setVisibility(View.GONE);
                break;
        }
    }

    @Override
    public void onClick(View v) {
        String phone = et_phone.getText().toString();
        if (phone.length() < 11) {
            Toast.makeText(this, "请输入正确的手机号", Toast.LENGTH_SHORT).show();
            return;
        }
        switch(v.getId()) {
            case R.id.btn_forget:
                // 选择了密码方式校验，此时要跳到找回密码页面
                if (rb_password.isChecked()) {
                    // 以下携带手机号码跳转到找回密码页面
                    Intent intent = new Intent(this, LoginForgetActivity.class);
                    intent.putExtra("phone", phone);
                     register.launch(intent);
                } else if (rb_verifycode.isChecked()) {
                    // 生成六位随机数字的验证码
                    mVerifyCode = String.format("%06d", new Random().nextInt(999999));
                    // 以下弹出提醒对话框，提示用户记住六位验证码数字
                    AlertDialog.Builder builder = new AlertDialog.Builder(this);
                    builder.setTitle("请记住验证码");
                    builder.setMessage("手机号" + phone + ",本次验证码是" + mVerifyCode + ",请输入验证码");
                    builder.setPositiveButton("好的", null);
                    AlertDialog dialog = builder.create();
                    dialog.show();
                }
                break;
            case R.id.btn_login:
                // 密码方式校验
                if (rb_password.isChecked()) {
                    if (!mPassword.equals(et_password.getText().toString())) {
                        Toast.makeText(this, "请输入正确的密码", Toast.LENGTH_SHORT).show();
                        return;
                    }
                    // 提示用户登录成功
                    loginSuccess();
                } else if (rb_verifycode.isChecked()) {
                    // 验证码方式校验
                    if (!mPassword.equals(et_password.getText().toString())) {
                        Toast.makeText(this, "请输入正确的验证码", Toast.LENGTH_SHORT).show();
                        return;
                    }
                    // 提示用户登录成功
                    loginSuccess();
                }
                break;
        }
    }

    private void loginSuccess() {
        String desc = String.format("您的手机号码是%s，恭喜你通过登录验证，点击“确定“按钮返回上个页面",
                et_phone.getText().toString());
        // 以下弹出提醒对话框，提示用户登录成功
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("登录成功");
        builder.setMessage(desc);
        builder.setPositiveButton("确定返回", (dialog, which) -> {
            // 结束当前的活动页面
            finish();
        });
        builder.setNegativeButton("我再看看", null);
        AlertDialog dialog = builder.create();
        dialog.show();

        if (ck_remember.isChecked()) {
            SharedPreferences.Editor editor = preferences.edit();
            editor.putString("phone", et_phone.getText().toString());
            editor.putString("password", et_password.getText().toString());
            editor.putBoolean("isRember", ck_remember.isChecked());
            editor.commit();
        }
    }

    // 定义一个编辑框监听器，在输入文本达到指定长度时自动隐藏输入法
    private class HideTextWatcher implements TextWatcher {
        private EditText mView;
        private int maxLength;
        public HideTextWatcher(EditText v, int maxLength) {
            this.mView = v;
            this.maxLength = maxLength;
        }

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

        }

        @Override
        public void afterTextChanged(Editable s) {
            if (s.toString().length() == maxLength) {
                // 隐藏输入法软键盘
                ViewUnil.hideOneInputMethod(LoginMainActivity.this, mView);
            }
        }
    }
}

1.2效果：

 退出应用：

 

 重新进入APP，从SharedPreferences中读取数据：

2.SQLiteDatabase

2.1activity_database.xml

<?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">

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

        <Button
            android:id="@+id/btn_database_create"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="创建数据库"
            android:textColor="@color/black"
            android:textSize="17sp" />

        <Button
            android:id="@+id/btn_database_delete"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="删除数据库"
            android:textColor="@color/black"
            android:textSize="17sp" />

    </LinearLayout>

    <TextView
        android:id="@+id/tv_database"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingLeft="5dp"
        android:textColor="@color/black"
        android:textSize="17sp" />

</LinearLayout>

2.2DatabaseActivity.java

package com.example.chapter06;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class DatabaseActivity extends AppCompatActivity implements View.OnClickListener {

    private TextView tv_database;
    private String mDatabaseName;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_database);
        tv_database = findViewById(R.id.tv_database);
        findViewById(R.id.btn_database_create).setOnClickListener(this);
        findViewById(R.id.btn_database_delete).setOnClickListener(this);
        // 生成一个测试数据库的完整路径
        mDatabaseName = getFilesDir() + "/test.db";
    }

    @Override
    public void onClick(View v) {
        String desc = "";
        switch (v.getId()) {
            case R.id.btn_database_create:
                // 创建或打开数据库，数据库如果不存在就创建它，如果存在就打开它
                SQLiteDatabase db = openOrCreateDatabase(mDatabaseName, Context.MODE_PRIVATE, null);
                desc = String.format("数据库%s创建%s", db.getPath(), (db!=null)?"成功":"失败");
                tv_database.setText(desc);
                break;
            case R.id.btn_database_delete:
                // 删除数据库
                boolean result = deleteDatabase(mDatabaseName);
                desc = String.format("数据库%s删除%s", mDatabaseName, result?"成功":"失败");
                tv_database.setText(desc);
                break;

        }
    }
}

2.3效果：