در این مقاله قصد داریم که یک فایلی را در یک edittext بنویسیم و بعد از ذخیره کردن آن دوباره آن را نمایش دهیم و بعد از نمایش دادن در یک فایل word ذخیره شود و بتوانیم آدرس فایل ذخیره شده را پیدا نماییم.

ابتدا برای خواندن و نوشتن فایل از مجوز های زیر استفاده می نماییم:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

یک پروژه به صورت زیر ایجاد نماییید:

در لایه activity قطعه کد زیر را قرار دهید:

<RelativeLayout 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">
 
    <EditText
        android:id="@+id/editText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true">
 
        <requestFocus />
    </EditText>
 
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="120dp"
        android:id="@+id/textView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/editText"
        android:layout_above="@+id/button_save"
        android:layout_marginTop="10dp" />
 
    <Button
        android:id="@+id/button_save"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="save"
        android:layout_alignParentBottom="true"
        android:layout_alignLeft="@+id/textView"
        android:layout_alignStart="@+id/textView" />
 
    <Button
        android:id="@+id/button_read"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button_save"
        android:layout_alignBottom="@+id/button_save"
        android:layout_toRightOf="@+id/button_save"
        android:text="read" />
 
    <Button
        style="?android:attr/buttonStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="List Dirs"
        android:id="@+id/button_list"
        android:layout_alignBottom="@+id/button_read"
        android:layout_toRightOf="@+id/button_read"
        android:layout_toEndOf="@+id/button_read" />
 
</RelativeLayout>

در کلاس جاوا قطعه کد زیر را قرار دهید:

import android.Manifest;
import android.app.Activity;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Environment;
import android.support.v4.app.ActivityCompat;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
 
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
 
public class MainActivity extends Activity {
   private EditText editText;
   private TextView textView;
   private Button saveButton;
   private Button readButton;
   private Button listButton;
 
 
   private static final int REQUEST_ID_READ_PERMISSION = 100;
   private static final int REQUEST_ID_WRITE_PERMISSION = 200;
 
   private final String fileName = "note.txt";
 
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main);
 
       editText = (EditText) findViewById(R.id.editText);
       textView = (TextView) findViewById(R.id.textView);
 
       saveButton = (Button) findViewById(R.id.button_save);
       readButton = (Button) findViewById(R.id.button_read);
       listButton = (Button) findViewById(R.id.button_list);
 
       saveButton.setOnClickListener(new OnClickListener() {
 
           @Override
           public void onClick(View arg0) {
               askPermissionAndWriteFile();
           }
 
       });
 
 
       readButton.setOnClickListener(new OnClickListener() {
 
           @Override
           public void onClick(View arg0) {
               askPermissionAndReadFile();
           }
 
       });
 
       listButton.setOnClickListener(new OnClickListener() {
 
           @Override
           public void onClick(View arg0) {
               listExternalStorages();
           }
 
       });
   }
 
   private void askPermissionAndWriteFile() {
       boolean canWrite = this.askPermission(REQUEST_ID_WRITE_PERMISSION,
               Manifest.permission.WRITE_EXTERNAL_STORAGE);
       //
       if (canWrite) {
           this.writeFile();
       }
   }
 
   private void askPermissionAndReadFile() {
       boolean canRead = this.askPermission(REQUEST_ID_READ_PERMISSION,
               Manifest.permission.READ_EXTERNAL_STORAGE);
       //
       if (canRead) {
           this.readFile();
       }
   }
 
   // With Android Level >= 23, you have to ask the user
   // for permission with device (For example read/write data on the device).
   private boolean askPermission(int requestId, String permissionName) {
       if (android.os.Build.VERSION.SDK_INT >= 23) {
 
           // Check if we have permission
           int permission = ActivityCompat.checkSelfPermission(this, permissionName);
 
 
           if (permission != PackageManager.PERMISSION_GRANTED) {
               // If don't have permission so prompt the user.
               this.requestPermissions(
                       new String[]{permissionName},
                       requestId
               );
               return false;
           }
       }
       return true;
   }
 
 
   // When you have the request results
   @Override
   public void onRequestPermissionsResult(int requestCode,
                                          String permissions[], int[] grantResults) {
 
       super.onRequestPermissionsResult(requestCode, permissions, grantResults);
       //
       // Note: If request is cancelled, the result arrays are empty.
       if (grantResults.length > 0) {
           switch (requestCode) {
               case REQUEST_ID_READ_PERMISSION: {
                   if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                       readFile();
                   }
               }
               case REQUEST_ID_WRITE_PERMISSION: {
                   if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                       writeFile();
                   }
               }
           }
       } else {
           Toast.makeText(getApplicationContext(), "Permission Cancelled!", Toast.LENGTH_SHORT).show();
       }
   }
 
 
   private void writeFile() {
   
       File extStore = Environment.getExternalStorageDirectory();
       // ==> /storage/emulated/0/note.txt
       String path = extStore.getAbsolutePath() + "/" + fileName;
       Log.i("ExternalStorageDemo", "Save to: " + path);
 
       String data = editText.getText().toString();
 
       try {
           File myFile = new File(path);
           myFile.createNewFile();
           FileOutputStream fOut = new FileOutputStream(myFile);
           OutputStreamWriter myOutWriter = new OutputStreamWriter(fOut);
           myOutWriter.append(data);
           myOutWriter.close();
           fOut.close();
 
           Toast.makeText(getApplicationContext(), fileName + " saved", Toast.LENGTH_LONG).show();
       } catch (Exception e) {
           e.printStackTrace();
       }
   }
 
   private void readFile() {
   
       File extStore = Environment.getExternalStorageDirectory();
       // ==> /storage/emulated/0/note.txt
       String path = extStore.getAbsolutePath() + "/" + fileName;
       Log.i("ExternalStorageDemo", "Read file: " + path);
 
       String s = "";
       String fileContent = "";
       try {
           File myFile = new File(path);
           FileInputStream fIn = new FileInputStream(myFile);
           BufferedReader myReader = new BufferedReader(
                   new InputStreamReader(fIn));
 
           while ((s = myReader.readLine()) != null) {
               fileContent += s + "\n";
           }
           myReader.close();
 
           this.textView.setText(fileContent);
       } catch (IOException e) {
           e.printStackTrace();
       }
       Toast.makeText(getApplicationContext(), fileContent, Toast.LENGTH_LONG).show();
   }
 
   private void listExternalStorages() {
       StringBuilder sb = new StringBuilder();
 
       sb.append("Data Directory: ").append("\n - ")
               .append(Environment.getDataDirectory().toString()).append("\n");
 
       sb.append("Download Cache Directory: ").append("\n - ")
               .append(Environment.getDownloadCacheDirectory().toString()).append("\n");
 
       sb.append("External Storage State: ").append("\n - ")
               .append(Environment.getExternalStorageState().toString()).append("\n");
 
       sb.append("External Storage Directory: ").append("\n - ")
               .append(Environment.getExternalStorageDirectory().toString()).append("\n");
 
       sb.append("Is External Storage Emulated?: ").append("\n - ")
               .append(Environment.isExternalStorageEmulated()).append("\n");
 
       sb.append("Is External Storage Removable?: ").append("\n - ")
               .append(Environment.isExternalStorageRemovable()).append("\n");
 
       sb.append("External Storage Public Directory (Music): ").append("\n - ")
               .append(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC).toString()).append("\n");
 
       sb.append("Download Cache Directory: ").append("\n - ")
               .append(Environment.getDownloadCacheDirectory().toString()).append("\n");
 
       sb.append("Root Directory: ").append("\n - ")
               .append(Environment.getRootDirectory().toString()).append("\n");
 
       Log.i("ExternalStorageDemo", sb.toString());
       this.textView.setText(sb.toString());
   }
 
}

در کلاس بالا ابزارها تعریف شده است و برای هر دکمه رویداد نوشته شده است یک فایل تکست هم نام گذاری شده است، برای ذخیره کردن متن و خواندن آن و نمایش دادن از مجوز هایی که در android manifest استفاده شده است استفاده می کنیم، اگر دکمه مسیر فایل هم بزنید آدرس آن نمایش داده می شود که شما می توانید آن را ببینید.

خروجی به صورت زیر خواهد بود: