效果图
填入正确的用户名和密码
跳转到登录成功界面
填入错误的用户名和密码
提示用户名和密码不符
开始实现
要求：
编写一个登录界面和一个登录成功界面, 结合自己的登录界面中的输入内容,将其用SharedPreferences方式存储,并且在登录的时候做一下逻辑判断进行数据比较，只有数据一致之后才能跳转到登录成功界面,否则做相应的错误提示
登录页面布局
根据需求设计登录界面activity_main.xml，这里用到了两个ImageView、两个EditText和一个Button按钮
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| <?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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="@drawable/back"
tools:context=".MainActivity">
<EditText
android:id="@+id/usr"
android:layout_width="250dp"
android:layout_height="40dp"
android:layout_marginTop="60dp"
android:background="@null"
android:hint="请输入用户名"
android:imeOptions="actionSend"
android:inputType="text"
android:padding="5dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.38"
app:layout_constraintStart_toEndOf="@+id/imageView3"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="@+id/pwd"
android:layout_width="250dp"
android:layout_height="40dp"
android:layout_marginTop="10dp"
android:background="@null"
android:hint="请输入密码"
android:imeOptions="actionSend"
android:inputType="text"
android:padding="5dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.38"
app:layout_constraintStart_toEndOf="@+id/imageView4"
app:layout_constraintTop_toBottomOf="@+id/usr" />
<Button
android:id="@+id/login"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="44dp"
android:text="登录"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/pwd" />
<ImageView
android:id="@+id/imageView3"
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_marginStart="30dp"
android:layout_marginTop="60dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="@drawable/usr" />
<ImageView
android:id="@+id/imageView4"
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_marginStart="30dp"
android:layout_marginTop="10dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/imageView3"
app:srcCompat="@drawable/pwd" />
</androidx.constraintlayout.widget.ConstraintLayout>
|
数据判断能否登录
在MainActivity中先将正确的用户名和密码用SharedPreferences方式存储，再和自己的登录界面中的输入内容做一下逻辑判断进行数据比较
如果符合，跳转到登录成功界面，否则提示错误
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| package com.huatec.edu.hw8avtivity;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
EditText usr;
EditText pwd;
Button login;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
usr = findViewById(R.id.usr);
pwd = findViewById(R.id.pwd);
login = findViewById(R.id.login);
login.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
SharedPreferences sharedPreferences = getSharedPreferences("user",MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString("user_name","tian");
editor.putString("pass_word","18");
editor.apply();
String user_name = sharedPreferences.getString("user_name",null);
String pass_word = sharedPreferences.getString("pass_word",null);
String username = usr.getText().toString();
String password = pwd.getText().toString();
if(user_name.equals(username) && pass_word.equals(password)) {
Intent intent = new Intent(MainActivity.this,Main2Activity.class);
startActivity(intent);
} else {
Toast.makeText(getApplicationContext(),"用户名或密码不符",Toast.LENGTH_LONG).show();
}
}
});
}
}
|
登录成功界面
activity_main2.xml
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| <?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
tools:context=".Main2Activity">
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="登录成功"
android:textSize="25sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
|
Main2Activity
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| package com.huatec.edu.hw8avtivity;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
public class Main2Activity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
}
}
|
