Android example source code file (ExternalStorage.java)

This example Android source code file (ExternalStorage.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, broadcastreceiver, button, content, error, externalstorage, file, fileoutputstream, inputstream, io, ioexception, item, os, outputstream, override, scanned, string, ui, uri, view

The ExternalStorage.java Android example source code

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.content;

//Need the following import to get access to the app resources, since this
//class is in a sub-package.
import com.example.android.apis.R;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.media.MediaScannerConnection;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;


/**
* Demonstration of styled text resources.
*/
public class ExternalStorage extends Activity {
    ViewGroup mLayout;

    static class Item {
        View mRoot;
        Button mCreate;
        Button mDelete;
    }

    Item mExternalStoragePublicPicture;
    Item mExternalStoragePrivatePicture;
    Item mExternalStoragePrivateFile;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.external_storage);
        mLayout = (ViewGroup)findViewById(R.id.layout);
        mExternalStoragePublicPicture = createStorageControls(
                "Picture: getExternalStoragePublicDirectory",
                Environment.getExternalStoragePublicDirectory(
                        Environment.DIRECTORY_PICTURES),
                new View.OnClickListener() {
                    public void onClick(View v) {
                        createExternalStoragePublicPicture();
                        updateExternalStorageState();
                    }
                },
                new View.OnClickListener() {
                    public void onClick(View v) {
                        deleteExternalStoragePublicPicture();
                        updateExternalStorageState();
                    }
                });
        mLayout.addView(mExternalStoragePublicPicture.mRoot);
        mExternalStoragePrivatePicture = createStorageControls(
                "Picture getExternalFilesDir",
                getExternalFilesDir(Environment.DIRECTORY_PICTURES),
                new View.OnClickListener() {
                    public void onClick(View v) {
                        createExternalStoragePrivatePicture();
                        updateExternalStorageState();
                    }
                },
                new View.OnClickListener() {
                    public void onClick(View v) {
                        deleteExternalStoragePrivatePicture();
                        updateExternalStorageState();
                    }
                });
        mLayout.addView(mExternalStoragePrivatePicture.mRoot);
        mExternalStoragePrivateFile = createStorageControls(
                "File getExternalFilesDir",
                getExternalFilesDir(null),
                new View.OnClickListener() {
                    public void onClick(View v) {
                        createExternalStoragePrivateFile();
                        updateExternalStorageState();
                    }
                },
                new View.OnClickListener() {
                    public void onClick(View v) {
                        deleteExternalStoragePrivateFile();
                        updateExternalStorageState();
                    }
                });
        mLayout.addView(mExternalStoragePrivateFile.mRoot);

        startWatchingExternalStorage();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        stopWatchingExternalStorage();
    }

    void handleExternalStorageState(boolean available, boolean writeable) {
        boolean has = hasExternalStoragePublicPicture();
        mExternalStoragePublicPicture.mCreate.setEnabled(writeable && !has);
        mExternalStoragePublicPicture.mDelete.setEnabled(writeable && has);
        has = hasExternalStoragePrivatePicture();
        mExternalStoragePrivatePicture.mCreate.setEnabled(writeable && !has);
        mExternalStoragePrivatePicture.mDelete.setEnabled(writeable && has);
        has = hasExternalStoragePrivateFile();
        mExternalStoragePrivateFile.mCreate.setEnabled(writeable && !has);
        mExternalStoragePrivateFile.mDelete.setEnabled(writeable && has);
    }


    BroadcastReceiver mExternalStorageReceiver;
    boolean mExternalStorageAvailable = false;
    boolean mExternalStorageWriteable = false;

    void updateExternalStorageState() {
        String state = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(state)) {
            mExternalStorageAvailable = mExternalStorageWriteable = true;
        } else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
            mExternalStorageAvailable = true;
            mExternalStorageWriteable = false;
        } else {
            mExternalStorageAvailable = mExternalStorageWriteable = false;
        }
        handleExternalStorageState(mExternalStorageAvailable,
                mExternalStorageWriteable);
    }

    void startWatchingExternalStorage() {
        mExternalStorageReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                Log.i("test", "Storage: " + intent.getData());
                updateExternalStorageState();
            }
        };
        IntentFilter filter = new IntentFilter();
        filter.addAction(Intent.ACTION_MEDIA_MOUNTED);
        filter.addAction(Intent.ACTION_MEDIA_REMOVED);
        registerReceiver(mExternalStorageReceiver, filter);
        updateExternalStorageState();
    }

    void stopWatchingExternalStorage() {
        unregisterReceiver(mExternalStorageReceiver);
    }



    void createExternalStoragePublicPicture() {
        // Create a path where we will place our picture in the user's
        // public pictures directory.  Note that you should be careful about
        // what you place here, since the user often manages these files.  For
        // pictures and other media owned by the application, consider
        // Context.getExternalMediaDir().
        File path = Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES);
        File file = new File(path, "DemoPicture.jpg");

        try {
            // Make sure the Pictures directory exists.
            path.mkdirs();

            // Very simple code to copy a picture from the application's
            // resource into the external file.  Note that this code does
            // no error checking, and assumes the picture is small (does not
            // try to copy it in chunks).  Note that if external storage is
            // not currently mounted this will silently fail.
            InputStream is = getResources().openRawResource(R.drawable.balloons);
            OutputStream os = new FileOutputStream(file);
            byte[] data = new byte[is.available()];
            is.read(data);
            os.write(data);
            is.close();
            os.close();

            // Tell the media scanner about the new file so that it is
            // immediately available to the user.
            MediaScannerConnection.scanFile(this,
                    new String[] { file.toString() }, null,
                    new MediaScannerConnection.OnScanCompletedListener() {
                public void onScanCompleted(String path, Uri uri) {
                    Log.i("ExternalStorage", "Scanned " + path + ":");
                    Log.i("ExternalStorage", "-> uri=" + uri);
                }
            });
        } catch (IOException e) {
            // Unable to create file, likely because external storage is
            // not currently mounted.
            Log.w("ExternalStorage", "Error writing " + file, e);
        }
    }

    void deleteExternalStoragePublicPicture() {
        // Create a path where we will place our picture in the user's
        // public pictures directory and delete the file.  If external
        // storage is not currently mounted this will fail.
        File path = Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES);
        File file = new File(path, "DemoPicture.jpg");
        file.delete();
    }

    boolean hasExternalStoragePublicPicture() {
        // Create a path where we will place our picture in the user's
        // public pictures directory and check if the file exists.  If
        // external storage is not currently mounted this will think the
        // picture doesn't exist.
        File path = Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES);
        File file = new File(path, "DemoPicture.jpg");
        return file.exists();
    }



    void createExternalStoragePrivatePicture() {
        // Create a path where we will place our picture in our own private
        // pictures directory.  Note that we don't really need to place a
        // picture in DIRECTORY_PICTURES, since the media scanner will see
        // all media in these directories; this may be useful with other
        // media types such as DIRECTORY_MUSIC however to help it classify
        // your media for display to the user.
        File path = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
        File file = new File(path, "DemoPicture.jpg");

        try {
            // Very simple code to copy a picture from the application's
            // resource into the external file.  Note that this code does
            // no error checking, and assumes the picture is small (does not
            // try to copy it in chunks).  Note that if external storage is
            // not currently mounted this will silently fail.
            InputStream is = getResources().openRawResource(R.drawable.balloons);
            OutputStream os = new FileOutputStream(file);
            byte[] data = new byte[is.available()];
            is.read(data);
            os.write(data);
            is.close();
            os.close();

            // Tell the media scanner about the new file so that it is
            // immediately available to the user.
            MediaScannerConnection.scanFile(this,
                    new String[] { file.toString() }, null,
                    new MediaScannerConnection.OnScanCompletedListener() {
                public void onScanCompleted(String path, Uri uri) {
                    Log.i("ExternalStorage", "Scanned " + path + ":");
                    Log.i("ExternalStorage", "-> uri=" + uri);
                }
            });
        } catch (IOException e) {
            // Unable to create file, likely because external storage is
            // not currently mounted.
            Log.w("ExternalStorage", "Error writing " + file, e);
        }
    }

    void deleteExternalStoragePrivatePicture() {
        // Create a path where we will place our picture in the user's
        // public pictures directory and delete the file.  If external
        // storage is not currently mounted this will fail.
        File path = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
        if (path != null) {
            File file = new File(path, "DemoPicture.jpg");
            file.delete();
        }
    }

    boolean hasExternalStoragePrivatePicture() {
        // Create a path where we will place our picture in the user's
        // public pictures directory and check if the file exists.  If
        // external storage is not currently mounted this will think the
        // picture doesn't exist.
        File path = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
        if (path != null) {
            File file = new File(path, "DemoPicture.jpg");
            return file.exists();
        }
        return false;
    }



     void createExternalStoragePrivateFile() {
         // Create a path where we will place our private file on external
         // storage.
         File file = new File(getExternalFilesDir(null), "DemoFile.jpg");

         try {
             // Very simple code to copy a picture from the application's
             // resource into the external file.  Note that this code does
             // no error checking, and assumes the picture is small (does not
             // try to copy it in chunks).  Note that if external storage is
             // not currently mounted this will silently fail.
             InputStream is = getResources().openRawResource(R.drawable.balloons);
             OutputStream os = new FileOutputStream(file);
             byte[] data = new byte[is.available()];
             is.read(data);
             os.write(data);
             is.close();
             os.close();
         } catch (IOException e) {
             // Unable to create file, likely because external storage is
             // not currently mounted.
             Log.w("ExternalStorage", "Error writing " + file, e);
         }
     }

     void deleteExternalStoragePrivateFile() {
         // Get path for the file on external storage.  If external
         // storage is not currently mounted this will fail.
         File file = new File(getExternalFilesDir(null), "DemoFile.jpg");
         if (file != null) {
             file.delete();
         }
     }

     boolean hasExternalStoragePrivateFile() {
         // Get path for the file on external storage.  If external
         // storage is not currently mounted this will fail.
         File file = new File(getExternalFilesDir(null), "DemoFile.jpg");
         if (file != null) {
             return file.exists();
         }
         return false;
     }


    Item createStorageControls(CharSequence label, File path,
            View.OnClickListener createClick,
            View.OnClickListener deleteClick) {
        LayoutInflater inflater = (LayoutInflater)getSystemService(LAYOUT_INFLATER_SERVICE);
        Item item = new Item();
        item.mRoot = inflater.inflate(R.layout.external_storage_item, null);
        TextView tv = (TextView)item.mRoot.findViewById(R.id.label);
        tv.setText(label);
        if (path != null) {
            tv = (TextView)item.mRoot.findViewById(R.id.path);
            tv.setText(path.toString());
        }
        item.mCreate = (Button)item.mRoot.findViewById(R.id.create);
        item.mCreate.setOnClickListener(createClick);
        item.mDelete = (Button)item.mRoot.findViewById(R.id.delete);
        item.mDelete.setOnClickListener(deleteClick);
        return item;
    }
}