内部存储InternalStorage(慕课)

 

 

 

 

package com.example.testapplication;

import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

import androidx.annotation.Nullable;

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

public class InternalActivity extends ApplicationActivity{
    EditText edt;
    TextView txt;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_internal);
        edt = findViewById(R.id.editText);
        txt = findViewById(R.id.textView7);
    }
    public void operate(View view){
        File f = new File(getFilesDir(),"getFilesDirs.txt");
        switch (view.getId()){
            case R.id.save_btn2:
                try {
                    if (!f.exists()) {
                        f.createNewFile();
                    }
                    FileOutputStream fos = new FileOutputStream(f);
                    fos.write(edt.getText().toString().getBytes());
                    fos.close();
                }catch (IOException e){
                    e.printStackTrace();
                }
                break;
            case R.id.read_btn2:
                try {
                    FileInputStream fis = new FileInputStream(f);
                    byte[] b = new byte[1024];
                    int len = fis.read(b);
                    String str2 = new String(b,0,len);
                    txt.setText(str2);
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                break;

        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <EditText
        android:id="@+id/editText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="22dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:maxLines="12"
        android:minLines="12"
        android:hint="请输入待存储的内容..."
        android:gravity="left|top"
        />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        >
        <Button
            android:id="@+id/read_btn2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginTop="8dp"
            android:layout_marginBottom="8dp"
            android:text="读取"
            android:onClick="operate" />

        <Button
            android:id="@+id/save_btn2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginTop="8dp"
            android:layout_marginBottom="8dp"
            android:text="保存"
            android:onClick="operate" />

    </LinearLayout>

    <TextView
        android:id="@+id/textView7"
        android:layout_width="match_parent"
        android:layout_height="176dp"
        android:layout_marginStart="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginBottom="32dp"
        />

</LinearLayout>