Android Studio获取共享首选项中的所有成员

问题描述 投票：0回答：1

我使用Java中的SharedPreferences构建了一个简单的注册和登录应用。用户注册他的信息并登录。登录后，应用程序仅在屏幕上显示其信息。我想要的是我想在DisplayScreen活动中显示所有注册会员的信息列表。我该怎么办？

您可以在下面看到我所有的xml和java文件。

activity_main xml：

<?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:paddingBottom="16dp"
    android:paddingLeft="16dp"
    android:paddingRight="16dp"
    android:paddingTop="16dp"
    tools:context=".MainActivity">


    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:ems="10"
        android:id="@+id/etName"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="75dp"
        android:hint="Enter Name" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPassword"
        android:ems="10"
        android:id="@+id/etPassword"
        android:layout_below="@+id/etName"
        android:layout_centerHorizontal="true"
        android:hint="Enter Password" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Login"
        android:id="@+id/btnLogin"
        android:layout_below="@+id/etPassword"
        android:layout_alignLeft="@+id/etPassword"
        android:layout_alignStart="@+id/etPassword" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Register"
        android:id="@+id/btnRegister"
        android:layout_alignTop="@+id/btnLogin"
        android:layout_toRightOf="@+id/btnLogin"
        android:layout_toEndOf="@+id/btnLogin" />
</RelativeLayout>

MainActivity.java：

package com.example.odev1v2;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

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

        final EditText etName = (EditText) findViewById(R.id.etName);
        final EditText etPassword = (EditText) findViewById(R.id.etPassword);
        Button btnLogin = (Button) findViewById(R.id.btnLogin);
        Button btnRegister = (Button) findViewById(R.id.btnRegister);

        btnLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String user = etName.getText().toString();
                String password = etPassword.getText().toString();
                SharedPreferences preferences = getSharedPreferences("MYPREFS", MODE_PRIVATE);

                String userDetails = preferences.getString(user + password + "data","NO INFO.");
                SharedPreferences.Editor editor = preferences.edit();
                editor.putString("display",userDetails);
                editor.commit();
                if(userDetails.equals("NO INFO.")){
                    Toast.makeText(getApplicationContext(), "FAIL", Toast.LENGTH_LONG).show();
                }
                else{
                    Intent displayScreen = new Intent(MainActivity.this, DisplayScreen.class);
                    startActivity(displayScreen);
                }
            }
        });

        btnRegister.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent registerScreen = new Intent(MainActivity.this, Register.class);
                startActivity(registerScreen);
            }
        });
    }
}

display_info.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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=".DisplayScreen">

    <TextView
        android:textSize="20sp"
        android:textStyle="bold"
        android:layout_width="150dp"
        android:layout_height="50dp"
        android:text="New Text"
        android:id="@+id/textViewName"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="100dp" />
</RelativeLayout>

DisplayScreen.java：

package com.example.odev1v2;

import androidx.appcompat.app.AppCompatActivity;

import android.content.SharedPreferences;
import android.os.Bundle;
import android.widget.TextView;

public class DisplayScreen extends AppCompatActivity {

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

        SharedPreferences preferences = getSharedPreferences("MYPREFS", MODE_PRIVATE);
        String display = preferences.getString("display", "");

        TextView displayInfo = (TextView) findViewById(R.id.textViewName);
        displayInfo.setText(display);

    }
}

register.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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=".Register">
    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:ems="10"
        android:id="@+id/etNewName"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="58dp"
        android:hint="Enter Name" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPassword"
        android:ems="10"
        android:id="@+id/etNewPassword"
        android:layout_below="@+id/etNewName"
        android:layout_centerHorizontal="true"
        android:hint="Enter Password" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/etNewEmail"
        android:layout_below="@+id/etNewPassword"
        android:layout_alignLeft="@+id/etNewPassword"
        android:layout_alignStart="@+id/etNewPassword"
        android:layout_alignRight="@+id/etNewPassword"
        android:layout_alignEnd="@+id/etNewPassword"
        android:hint="Enter Email" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Register"
        android:id="@+id/btnNewRegister"
        android:layout_below="@+id/etNewEmail"
        android:layout_centerHorizontal="true" />

</RelativeLayout>

Register.java：

package com.example.odev1v2;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class Register extends AppCompatActivity {

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

        final EditText userName = (EditText) findViewById(R.id.etNewName);
        final EditText password = (EditText) findViewById(R.id.etNewPassword);
        final EditText email = (EditText) findViewById(R.id.etNewEmail);
        Button btnRegister = (Button) findViewById(R.id.btnNewRegister);


        btnRegister.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                SharedPreferences preferences = getSharedPreferences("MYPREFS",MODE_PRIVATE);
                String newUser  = userName.getText().toString();
                String newPassword = password.getText().toString();
                String newEmail = email.getText().toString();

                SharedPreferences.Editor editor = preferences.edit();

                editor.putString(newUser,newUser);
                editor.commit();
                editor.putString(newPassword, newPassword);
                editor.commit();
                editor.putString(newUser + newPassword + "data", newUser + "\n" + newEmail);
                editor.commit();

                Toast.makeText(getApplicationContext(), "SUCCESS.", Toast.LENGTH_LONG).show();
                Intent register2Main = new Intent(Register.this, MainActivity.class);
                startActivity(register2Main);
            }
        });

    }
}
java android android-studio authentication sharedpreferences
1个回答
0
投票

Bro，SharedPreferences仅将用户信息保存在手机上，如果要存储所有用户的数据，则需要像Firebase或SQLite这样的数据库。

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