Android第六次作业

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

    <TextView
        android:id="@+id/tv_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="5dp"
        android:background="#000000"
        android:padding="10dp"
        android:text="内部存储空间文件操作"
        android:textColor="#ffffff"
        android:textSize="25sp" />

    <EditText
        android:id="@+id/et_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="输入你想输入的内容" />

    <Button
        android:id="@+id/btn_1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#FFFFFF"
        android:onClick="click1"
        android:text="写入"
        android:textColor="#ffffff" />

    <EditText
        android:id="@+id/et_2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="显示读取的内容" />

    <Button
        android:id="@+id/btn_2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#2C2A2A"
        android:onClick="click2"
        android:text="读取"
        android:textColor="#ffffff" />

</LinearLayout>

package com.example.myapplication1;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import java.io.FileInputStream;
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);
    }
    public void click1(View view) {
        String filename = "data.txt";
        String content=((EditText)findViewById(R.id.et_1)).getText().toString();
        FileOutputStream fos = null;
        try {
            fos = openFileOutput(filename, MODE_PRIVATE);
            fos.write(content.getBytes());
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            if (fos != null)
                try {
                    fos.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
        }
        Toast.makeText(this, "保存成功", 0).show();
    }

    public void click2(View view) {
        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) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            if (fis != null)
                try {
                    fis.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
        }
        ((EditText) findViewById(R.id.et_2)).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:id="@+id/tv1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="15dp"
        android:background="#27D52C"
        android:padding="5dp"
        android:text="用户登录"
        android:textColor="#FFFFFF"
        android:textSize="25sp" />

    <LinearLayout
        android:id="@+id/ll_1"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_margin="10dp"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/tv2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:text="账号"
            android:textColor="#000000"
            android:textSize="18sp" />

        <EditText
            android:id="@+id/et1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:hint="请输入账号" />

    </LinearLayout>

    <LinearLayout
        android:id="@+id/ll_2"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_margin="10dp"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/tv3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:text="密码"
            android:textColor="#000000"
            android:textSize="18sp" />

        <EditText
            android:id="@+id/et2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:hint="请输入密码" />

    </LinearLayout>

    <LinearLayout
        android:id="@+id/ll_3"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:layout_marginLeft="25dp"
        android:orientation="horizontal">

        <CheckBox
            android:id="@+id/cb1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:text="记住密码" />

        <CheckBox
            android:id="@+id/cb2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:text="自动登录" />

        <Button
            android:id="@+id/btn1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:text="登录" />

    </LinearLayout>

</LinearLayout>

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.EditText;
import android.widget.Toast;

import java.util.Map;

public class MainActivity extends AppCompatActivity implements View.OnClickListener, CompoundButton.OnCheckedChangeListener {
    private EditText et_account;
    private EditText et_password;
    private Button btn_login;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        Map<String, String> userInfo = saveQQ.getUserInfo(this);
        if (userInfo != null) {
            et_account.setText(userInfo.get("account"));
            et_password.setText(userInfo.get("password"));

        }
    }

    private void initView() {
        et_account = (EditText) findViewById(R.id.et1);
        et_password = (EditText) findViewById(R.id.et2);
        btn_login = (Button) findViewById(R.id.btn1);
        btn_login.setOnClickListener(this);
        CheckBox cb1 = (CheckBox) findViewById(R.id.cb1);
        cb1.setOnCheckedChangeListener(this);
        CheckBox cb2 = (CheckBox) findViewById(R.id.cb2);
        cb2.setOnCheckedChangeListener(this);
    }

    @Override
    public void onClick(View v) {
        switch(v.getId()){
            case R.id.btn1:
                String account=et_account.getText().toString().trim();
                String password=et_password.getText().toString();
                if(TextUtils.isEmpty(account)){
                    Toast.makeText(this,"输入QQ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, "登录成功", Toast.LENGTH_SHORT).show();

        }

    }

    @Override
    public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
        switch (compoundButton.getId()){
            case R.id.cb1 :
                String account=et_account.getText().toString().trim();
                String password=et_password.getText().toString();
                boolean isSaveSuccess=saveQQ.SaveUserInfo(this, account, password);
                if(isSaveSuccess&&b){
                    Toast.makeText(this, "保存成功", Toast.LENGTH_SHORT).show();
                }else{
                    Toast.makeText(this, "保存失败", Toast.LENGTH_SHORT).show();
                    et_account.setText(null);
                    et_password.setText(null);
                }

                break;
            case R.id.cb2: account=et_account.getText().toString().trim();
                password=et_password.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;
                }
                if(b)
                    Toast.makeText(this, "登录成功", Toast.LENGTH_SHORT).show();
                else{
                    Toast.makeText(this, "请登录", Toast.LENGTH_SHORT).show();
                }

        }
    }
}

package com.example.myapplication;

import android.content.Context;
import android.content.SharedPreferences;

import java.util.HashMap;
import java.util.Map;

public class saveQQ {
    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("account", 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("account",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;
    }

}