Android第十一、十二周作业

图片一 用内部存储实现文件写入和读取功能

<?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"
    tools:context=".MainActivity"
    android:orientation="vertical">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="内部存储空间文件操作"
        android:textSize="20sp"
        android:textColor="#FFB6C1"/>

    <EditText
        android:id="@+id/a1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="输入你想要写入的内容" />

<Button
    android:id="@+id/b1"
    android:layout_width="100sp"
    android:layout_height="wrap_content"
    android:text="写入"
    android:textColor="#000000"
    android:onClick="click1"/>

    <EditText
        android:id="@+id/a2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="显示读取的内容" />

    <Button
        android:id="@+id/b2"
        android:layout_width="100sp"
        android:layout_height="wrap_content"
        android:text="读取"
        android:textColor="#000000"
        android:onClick="click2"/>

</LinearLayout>

package com.example.gcgc;

import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.view.View;
import android.os.Bundle;
import android.widget.EditText;
import android.widget.Toast;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    @SuppressLint("WrongConstant")
    public void click1(View view){
        EditText a1=findViewById(R.id.a1);
        EditText a2=findViewById(R.id.a2);
        String fileName ="data.txt";
        String content =a1.getText().toString();
        FileOutputStream fos =null;
        try{
            fos = openFileOutput(fileName,MODE_PRIVATE);
            fos.write(content.getBytes());
        }catch(Exception e){
            e.printStackTrace();
        }finally {
            try{
                if (fos!=null){
                    fos.close();
                }
            }catch(IOException e){
                e.printStackTrace();
            }
        }
        Toast.makeText(this,"保存成功",0).show();
    }
    @SuppressLint("WrongConstant")
    public void click2(View view){
        EditText a2 =findViewById(R.id.a2);
        String content="";
        FileInputStream fis =null;
        try{
            fis = openFileInput("data.txt");
            byte[] buffer =new byte[fis.available()];
            fis.read(buffer);
            content = new String(buffer);
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            try{
                if (fis!=null){
                    fis.close();
                }
            }    catch (IOException e) {
                e.printStackTrace();
            }
            a2.setText(content);
        }
    }
}

图片二 使用sharedpreference实现记住密码功能

<?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"
    tools:context=".MainActivity"
    android:orientation="vertical">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="用户登录"
        android:textColor="#FFC0CB"
        android:textSize="30dp"/>

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

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="账号"
            android:textColor="#D8BFD8"
            android:textSize="20dp"/>

        <EditText
            android:id="@+id/a1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="请输入用户名" />
    </LinearLayout>

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

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="密码"
            android:textColor="#D8BFD8"
            android:textSize="20dp"/>

        <EditText
            android:id="@+id/a2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="请输入密码" />
    </LinearLayout>

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

    <CheckBox
        android:id="@+id/b1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="记住密码"
        android:textSize="15dp" />

<CheckBox
    android:id="@+id/b2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="自动登录"
    android:textSize="15dp" />

    <Button
        android:id="@+id/c1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="登录"
        android:textSize="20dp"
        android:textColor="#9370DB"/>
</LinearLayout>
</LinearLayout>

package com.example.gc1;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.os.SharedMemory;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TableLayout;
import android.widget.Toast;

import java.io.FileInputStream;
import java.util.HashMap;
import java.util.Map;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private EditText a1;//账号输入框
private EditText a2;//密码输入框
private Button c1;//登录按钮
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initView();
        Map<String,String>userInfo = SPSaveQQ.getUserInfo(this);
        if (userInfo!=null){
            a1.setText(userInfo.get("account"));
            a2.setText(userInfo.get("pssword"));
        }
    }

    private void initView() {
        a1=(EditText)findViewById(R.id.a1);
        a2=(EditText)findViewById(R.id.a2);
        c1=(Button)findViewById(R.id.c1);
        c1.setOnClickListener(this);
    }

    public void onClick(View view){
        switch (view.getId()){
            case R.id.c1:
                String account =a1.getText().toString().trim();
                String password =a2.getText().toString();
                if (TextUtils.isEmpty(account)){
                    Toast.makeText(this,"请输入账号",Toast.LENGTH_SHORT).show();
                    return;
                }
                if (TextUtils.isEmpty(password)){
                    Toast.makeText(this,"请输入密码",Toast.LENGTH_SHORT).show();
                    return;
                }
                Toast.makeText(this,"登陆成功",Toast.LENGTH_SHORT).show();
                boolean isSaveSuccess =SPSaveQQ.saveUserInfo(this,account,password);
                if (isSaveSuccess){
                    Toast.makeText(this,"保存成功", Toast.LENGTH_SHORT).show();
                }else
                {
                    Toast.makeText(this,"保存失败",Toast.LENGTH_SHORT).show();

                }
                break;
        }
    }

    public static class SPSaveQQ{
        public static boolean saveUserInfo(Context context,String account,String password){
            SharedPreferences sp =context.getSharedPreferences("data",Context.MODE_PRIVATE);
            SharedPreferences.Editor edit =sp.edit();
            edit.putString("userName",account);
            edit.putString("pwd",password);
            edit.commit();
            return true;
        }
        public static Map<String,String> getUserInfo(Context context){
            SharedPreferences sp =context.getSharedPreferences("data",Context.MODE_PRIVATE);
            String account =sp.getString("userName",null);
            String password =sp.getString("pwd",null);
            Map<String,String> userMap =new HashMap<String, String>();
            userMap.put("account",account);
            userMap.put("password",password);
            return userMap;
        }
    }

}