This post shows how to create a text file in private app storage and access all files in private app storage.
In AndroidManifest.xml add a FileProvider.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.pickfile">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/Theme.PickFile">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".PrivateStorage"/>
<provider
android:name="androidx.core.content.FileProvider"
android:authorities="com.example.pickfile.provider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/provider_paths"/>
</provider>
</application>
</manifest>In xml folder in res/ and in res/xml/ add a file provider_paths.xml.
<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path name="external_files" path="."/>
</paths>
Create your layout in activity_main.xml.
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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">
<EditText
android:id="@+id/edittext1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:background="#efefcf"
android:padding="8dp"
android:gravity="start"
app:layout_constraintBottom_toTopOf="@+id/edittext2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="@+id/edittext2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:background="#efefef"
android:padding="8dp"
android:textSize="18sp"
android:hint="file_name"
android:gravity="start"
app:layout_constraintTop_toBottomOf="@id/edittext1"
app:layout_constraintBottom_toTopOf="@+id/button1"
app:layout_constraintEnd_toStartOf="@id/textview1"
app:layout_constraintStart_toStartOf="parent" />
<TextView
android:id="@+id/textview1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:padding="8dp"
android:text=".txt"
android:textStyle="bold"
android:textSize="18sp"
app:layout_constraintBottom_toTopOf="@+id/button1"
app:layout_constraintEnd_toEndOf="parent" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="4dp"
android:text="Save file"
android:textSize="16sp"
app:layout_constraintTop_toBottomOf="@id/edittext2"
app:layout_constraintEnd_toStartOf="@id/button2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"/>
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="4dp"
android:text="Private storage"
android:textSize="16sp"
app:layout_constraintTop_toBottomOf="@id/edittext2"
app:layout_constraintStart_toEndOf="@id/button1"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>In MainActivity.java use following codes.
package com.example.pickfile;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
public class MainActivity extends AppCompatActivity {
EditText edittext1, edittext2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button1 = findViewById(R.id.button1);
Button button2 = findViewById(R.id.button2);
edittext1 = findViewById(R.id.edittext1);
edittext2 = findViewById(R.id.edittext2);
button1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String folder = getExternalFilesDir(null).getAbsolutePath() + "/";
String filename = "newfile.txt";
if (!edittext2.getText().toString().equals("")){
filename = edittext2.getText().toString() + ".txt";
}
File newfile = new File(folder, filename);
String text = edittext1.getText().toString();
try {
FileWriter myWriter = new FileWriter(newfile);
myWriter.write(text);
myWriter.close();
Toast.makeText(getApplicationContext(),
"Successfully wrote to the file.", Toast.LENGTH_SHORT).show();
} catch (IOException e){
Toast.makeText(getApplicationContext(), e.toString(), Toast.LENGTH_SHORT).show();
}
}
});
button2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, PrivateStorage.class);
startActivity(intent);
}
});
}
}Create private_storage.xml in res/layout/ folder.
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.recyclerview.widget.RecyclerView
android:layout_width="0dp"
android:layout_height="0dp"
android:id="@+id/recyclerview1"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>Create recycler_item.xml in res/layout/ folder.
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#ffffcc">
<TextView
android:id="@+id/textView1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="TextView"
android:textSize="22sp"
android:textColor="#1f1eee"
android:padding="4dp"
android:gravity="start"
app:layout_constraintEnd_toStartOf="@id/imageView1"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="@+id/imageView1"
android:layout_width="40dp"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@id/textView1"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="@drawable/ic_more_vert_black_24dp" />
<TextView
android:id="@+id/textView2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:text="TextView"
android:textSize="18sp"
android:textColor="#6f6e6e"
android:padding="4dp"
android:paddingTop="2dp"
android:gravity="start"
app:layout_constraintEnd_toStartOf="@id/imageView1"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@id/textView1" />
</androidx.constraintlayout.widget.ConstraintLayout>Create new ja PrivateStorage.java use following codes.
package com.example.pickfile;
import android.content.ActivityNotFoundException;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.appcompat.widget.PopupMenu;
import androidx.core.content.FileProvider;
import androidx.recyclerview.widget.DividerItemDecoration;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import java.io.File;
public class PrivateStorage extends AppCompatActivity {
private RecyclerView mRecyclerView;
private File[] allfiles;
CustomAdapter mAdapter;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.private_storage);
mRecyclerView = (RecyclerView) findViewById(R.id.recyclerview1);
RecyclerView.LayoutManager mLayoutManager= new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
mRecyclerView.addItemDecoration(
new DividerItemDecoration(getApplicationContext(),
DividerItemDecoration.VERTICAL));
refreshAdapter();
}
private void refreshAdapter() {
String folder = getExternalFilesDir(null).getAbsolutePath() + "/";
File directory = new File(folder);
allfiles = directory.listFiles();
mAdapter = new CustomAdapter(allfiles);
mRecyclerView.setAdapter(mAdapter);
}
public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {
private final File[] files_list;
public CustomAdapter(File[] dataSet) {
files_list = dataSet;
}
@Override
public int getItemCount() {
return files_list.length;
}
public class ViewHolder extends RecyclerView.ViewHolder {
private final TextView textView1, textView2;
private final ImageView imageView;
public ViewHolder(View v) {
super(v);
textView1 = v.findViewById(R.id.textView1);
textView2 = v.findViewById(R.id.textView2);
imageView = v.findViewById(R.id.imageView1);
}
}
@Override @NonNull
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
// Create a new view.
View v = LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.recycler_item, viewGroup, false);
return new ViewHolder(v);
}
@Override
public void onBindViewHolder(ViewHolder viewHolder, final int position) {
String filepath = files_list[position].getAbsolutePath();
String filename = filepath.substring(filepath.lastIndexOf("/")+1);
viewHolder.textView1.setText(filename);
viewHolder.textView2.setText(filepath);
viewHolder.imageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View _v) {
PopupMenu popup = new PopupMenu(PrivateStorage.this, _v);
Menu menu = popup.getMenu();
menu.add("Open");
menu.add("Share");
menu.add("Delete");
popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener(){
@Override
public boolean onMenuItemClick(MenuItem item){
switch (item.getTitle().toString()){
case "Open":
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
intent.setDataAndType(FileProvider.getUriForFile(
PrivateStorage.this,
getApplicationContext().getPackageName() + ".provider",
files_list[position]), "text/*");
try {
startActivity(intent);
} catch (ActivityNotFoundException e) {
Toast.makeText(getApplicationContext(),
"No app found to open this file", Toast.LENGTH_SHORT).show();
}
break;
case "Share":
Intent iten = new Intent(android.content.Intent.ACTION_SEND);
iten.setType("text/*");
iten.putExtra(Intent.EXTRA_STREAM,
FileProvider.getUriForFile(
PrivateStorage.this,
getApplicationContext().getPackageName() + ".provider",
files_list[position]));
startActivity(Intent.createChooser(iten, "Send to"));
break;
case "Delete":
if (files_list[position].delete()){
refreshAdapter();
}
break;
}
return true;
}
});
popup.show();
}
});
}
}
}
Now run the app.