第十一、十二周作业

<?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"
    android:background="#F8E7FC"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/et_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入想写入的内容"
        android:textSize="20sp"
        android:layout_margin="20dp"
        android:padding="10dp"/>

    <Button
        android:id="@+id/btn_1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="保存"
        android:textColor="#000000"
        android:textSize="20sp"
        android:layout_marginLeft="25dp"
        android:padding="10dp"
        android:onClick="click1"/>

    <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"
        android:textSize="20sp"
        android:layout_margin="20dp"
        android:padding="10dp"/>

    <Button
        android:id="@+id/btn_2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="读取"
        android:textColor="#000000"
        android:textSize="20sp"
        android:layout_marginLeft="25dp"
        android:padding="10dp"
        android:onClick="click2"/>

</LinearLayout>

package com.example.lh7;

import androidx.appcompat.app.AppCompatActivity;

import android.icu.text.UnicodeSetSpanner;
import android.os.Bundle;
import android.view.View;
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);
        findViewById(R.id.btn_1);
        findViewById(R.id.btn_2);
    }

    public void click1(View view) {
        EditText editText1 = findViewById(R.id.et_1);
        EditText editText2 = findViewById(R.id.et_2);
        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_LONG).show();
    }

    public void click2(View view) {
        EditText editText2 = findViewById(R.id.et_2);
        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);
    }
}