Android – Read/Write to External Storage 12 September 2018 S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage 1

S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage Android External Storage: a place to store addition data  of Android, the files that you store here is not applied the security system. Usually there are two types of external storage:  Fixed external storage: Commonly understood as the hard drive of the device. Removable  storage: Such as SD Card.  Use the static method of Environment class  you can get the information on the directory of the external storage. 12 September 2018 S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage

S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage Android External Storage The table below results running on the emulator device. To read/write the data on the external storage requires you to configureAndroidManifest.xml, added: 12 September 2018 S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage

Read and write files on the external storage example AndroidManifest.xml configuration allows read and write data on the external storage memory. Full content of  AndroidManifest.xml: 12 September 2018 S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage

Read and write files on the external storage example activity_main.xml <?xml version="1.0" encoding="utf-8"?> <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_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_alignBaseline="@+id/button_save"         android:layout_alignBottom="@+id/button_save"         android:layout_toRightOf="@+id/button_save"         android:text="read" />         style="?android:attr/buttonStyleSmall"         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> 12 September 2018 S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage

Read and write files on the external storage example 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();            }        }); MainActivity.java 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; 12 September 2018 S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage

S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage MainActivity.java  Contd readButton.setOnClickListener(new OnClickListener() {              @Override            public void onClick(View arg0) {                askPermissionAndReadFile();            }        });        listButton.setOnClickListener(new OnClickListener() {                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(); 12 September 2018 S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage

S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage    // When you have the request results MainActivity.java  Contd   @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: {                        writeFile();            }        } else {            Toast.makeText(getApplicationContext(), "Permission Cancelled!", Toast.LENGTH_SHORT).show();        }    }  // 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;    } 12 September 2018 S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage

S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage MainActivity.java  Contd 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();    } 12 September 2018 S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage

S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage    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 - ")        sb.append("Root Directory: ").append("\n - ")                .append(Environment.getRootDirectory().toString()).append("\n");        Log.i("ExternalStorageDemo", sb.toString());        this.textView.setText(sb.toString());    } } MainActivity.java  Contd 12 September 2018 S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage

Read and write files on the external storage example Output 12 September 2018 S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage

S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage Thank You 12 September 2018 S.RENUKADEVI/AP/SCD/ANDROID - Read/Write to External Storage