Android06——实现简单的登录功能

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一、简介

1. 布局中使用了LinearLayout与RelativeLayout
2. 增加友好性使用了ToggleButton来控制显示与隐藏密码

二、效果图

三、核心代码

 1. activity_login.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
    tools:context=".LoginActivity">

    <TextView
        android:id="@+id/sign"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="用户登录"
        android:gravity="center"
        android:textStyle="bold"
        android:textSize="20sp"
         />
    <RelativeLayout
        android:id="@+id/main"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <TextView
            android:id="@+id/userLabel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/userLabel"
            android:layout_alignBaseline="@id/userNameText"
            android:text="用户名："
            android:textSize="20sp"/>
        <EditText
            android:id="@+id/userNameText"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_toRightOf="@id/userLabel"
            android:textSize="20sp"
            android:hint="请输入用户名"/>
        <TextView
            android:id="@+id/pswLabel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/userNameText"
            android:layout_alignBaseline="@id/passwordText"
            android:textSize="20sp"
            android:text="密 码："/>
        <EditText
            android:id="@+id/passwordText"
            android:layout_width="250dp"
            android:layout_height="wrap_content"
            android:layout_below="@id/userNameText"
            android:layout_toRightOf="@id/pswLabel"
            android:layout_alignLeft="@id/userNameText"
            android:inputType="textPassword"
            android:textSize="20sp"
            android:hint="请输入密码"/>
        <ToggleButton
            android:id="@+id/showPwd"
            android:layout_width="25dp"
            android:layout_height="25dp"
            android:layout_toRightOf="@id/passwordText"
            android:layout_below="@id/userNameText"
            android:layout_alignBaseline="@id/passwordText"
            android:background="@drawable/close"
            android:textOn=""
            android:textOff=""/>
        <TextView
            android:id="@+id/register"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/passwordText"
            android:layout_alignBaseline="@id/loginBtn"
            android:textSize="15sp"
            android:layout_marginLeft="20dp"
            android:text="注册"
            android:clickable="true"/>
        <Button
            android:id="@+id/resetBtn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="重置"
            android:layout_below="@id/passwordText"
            android:layout_toRightOf="@id/register"
            android:layout_marginLeft="100dp"
            android:textSize="20sp"
            android:textStyle="bold"/>
        <Button
            android:id="@+id/loginBtn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@id/passwordText"
            android:layout_toRightOf="@id/resetBtn"
            android:layout_alignRight="@id/passwordText"
            android:textSize="20sp"
            android:textStyle="bold"
            android:text="登录"/>
    </RelativeLayout>

</LinearLayout>

2. LoginActivity.java

package com.kjgym.demologin01;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.method.HideReturnsTransformationMethod;
import android.text.method.PasswordTransformationMethod;
import android.view.View;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ToggleButton;

public class LoginActivity extends AppCompatActivity {

    private Button resetBtn;
    private Button loginBtn;
    private TextView register;
    private EditText userNameText;
    private EditText passwordText;

    private ToggleButton showPwd;

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

        // 初始化
        init();
    }

    public void init(){
        resetBtn = findViewById(R.id.resetBtn);
        loginBtn = findViewById(R.id.loginBtn);
        register = findViewById(R.id.register);
        userNameText = findViewById(R.id.userNameText);
        passwordText = findViewById(R.id.passwordText);
        showPwd = findViewById(R.id.showPwd);

        // 显示密码功能实现
        showPwd.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if(isChecked){
                    // 显示密码
                    showPwd.setBackgroundResource(R.drawable.open);
                    passwordText.setTransformationMethod(HideReturnsTransformationMethod.getInstance());
                    // 将光标移至最后一行
                    passwordText.setSelection(passwordText.getText().toString().length());
                }else{
                    // 隐藏密码
                    showPwd.setBackgroundResource(R.drawable.close);
                    passwordText.setTransformationMethod(PasswordTransformationMethod.getInstance());
                    passwordText.setSelection(passwordText.getText().toString().length());
                }
            }
        });

        // 登录功能实现
        loginBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(getApplicationContext(),"登录功能尚未实现",Toast.LENGTH_LONG).show();
            }
        });

        // 注册功能实现
        register.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(getApplicationContext(),"注册功能尚未实现",Toast.LENGTH_LONG).show();
            }
        });

        // 重置功能实现
        resetBtn.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v){
                userNameText.setText("");
                passwordText.setText("");
                showPwd.setBackgroundResource(R.drawable.close);
            }
        });
    }
}