作业

1.

package com.example.charp1;

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

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

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

    public void click1(View view) {
        EditText editText1 = (EditText) findViewById(R.id.et1);
        EditText editText2 = (EditText) findViewById(R.id.et2);
        String filename = "data.txt";
        String context = editText1.getText().toString();
        FileOutputStream fos = null;
        try {
            fos = openFileOutput(filename, MODE_PRIVATE);
            fos.write(context.getBytes());
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        Toast.makeText(this, "保存成功", Toast.LENGTH_SHORT).show();

    }

    public void click2(View view) {
        EditText editText2 = (EditText) findViewById(R.id.et2);
        String context = "";
        FileInputStream fis = null;
        try {
            fis = openFileInput("data.txt");
            byte[] buffer = new byte[fis.available()];
            fis.read(buffer);
            context = new String(buffer);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (fis != null) {
                try {
                    fis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        editText2.setText(context);
    }
}

<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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity"
    android:orientation="vertical" >
  <EditText 
      android:id="@+id/et1"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:text="输入你想写入的内容"
      />
  <Button 
      android:id="@+id/bt1"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="写入"
      android:onClick="click1"/>
    <EditText 
      android:id="@+id/et2"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:text="显示读取的内容"
      />
   
  <Button 
      android:id="@+id/bt2"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="读取"
      android:onClick="click2"/>
  
  

    
    
    
   
</LinearLayout>

　　

 

 2.

<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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

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

        <TextView
            android:id="@+id/tv1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="账号：" />

        <EditText
            android:id="@+id/ed3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="请输入用户名" />
    </LinearLayout>

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

        <TextView
            android:id="@+id/tv2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="密码：" />

        <EditText
            android:id="@+id/ed4"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="请输入密码" />
    </LinearLayout>
  <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >
        <CheckBox
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="记住密码"/>
        <CheckBox
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="自动登录"/>
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="登录"
            android:onClick="click1"/>
</LinearLayout>
</LinearLayout>

　　

package com.example.charp2;



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

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.view.Menu;
import android.widget.EditText;

public class MainActivity extends Activity {

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


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
 
    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> getUserfo(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;
    }
}

　　

 

 

2.

<?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">

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

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="账号" />

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

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

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="密码" />

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

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

        <CheckBox
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="记住密码" />

        <CheckBox
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="自动登录" />

        <Button
            android:id="@+id/btn_login"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="onClick"
            android:text="登录" />
    </LinearLayout>

</LinearLayout>

　　

package com.example.qq;

import android.content.Context;

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

public class FileSaveQQ {
    public static boolean saveUserInfo(Context context, String account, String password ) {

        FileOutputStream fos = null;
        try{
            fos =context.openFileOutput("data.txt",Context.MODE_PRIVATE);
            fos.write((account+":"+password).getBytes());
            return true;

        }catch (Exception e){
            e.printStackTrace();
            return  false;

        }finally {
            try{
                if (fos !=null){
                    fos.close();
                }
            }catch (IOException e){
                e.printStackTrace();
            }
        }
    }
    public static Map<String, String> getUserInfo(Context context){
        String content="";
        FileInputStream fis= null;
        try {
            fis=context.openFileInput("data.txt");
            byte[] buffer =new byte[fis.available()];
            fis.read(buffer);
            content=new String(buffer);
            Map<String,String> userMap = new HashMap<String, String>();
            String[] infos = content.split(":");
            userMap.put("account",infos[0]);
            userMap.put("password",infos[1]);
            return userMap;

        }catch (Exception e){
            e.printStackTrace();
            return null;

        }
        finally {
            try {
                if (fis!=null){
                    fis.close();
                }
            }catch (IOException e){
                e.printStackTrace();
            }
        }
    }
}

package com.example.qq;

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

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

public 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;
    }
}

package com.example.qq;

import androidx.appcompat.app.AppCompatActivity;

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

import java.util.Map;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    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 = FileSaveQQ.getUserInfo(this);
        if (userInfo != null) {
            et_account.setText(userInfo.get("account"));
            et_password.setText(userInfo.get("password"));
        }
    }

    private void initView() {
        et_account = findViewById(R.id.et_account);
        et_password = findViewById(R.id.et_password);
        btn_login = findViewById(R.id.btn_login);
        btn_login.setOnClickListener(this);
    }


    @Override
    public void onClick(View view) {

        switch (view.getId()) {
            case R.id.btn_login:
                String account = et_account.getText().toString().trim();
                String password = et_password.getText().toString();
                if (TextUtils.isEmpty(account)) {
                    Toast.makeText(this, "请输入用户名", 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();
                boolean isSaveSuccess = FileSaveQQ.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;

        }
    }
}