Android Studio - Complete Android Apps Tutorial – Accessing Files - Day 16 - 2.09

Preferences  Stored as XML files at /data/data/package name/shared_prefs/  store user-specified configuration  key/value pairs e.g. key:sound value:true boolean key:username value:''android'' string
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 Run getDefaultSharedPreferencescontext from PreferencesManager, to access the shared preferences stored as package name_preferences.xml
SharedPreferences prefs = PreferenceManager. getDefaultSharedPreferences this;
selection = prefs.getString"selection", ""; year = prefs.getInt"year", 0;
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 Save to shared preferences manually  Call edit to obtain an Editor  Call apply to apply the changes to the shared preferences
SharedPreferences prefs = PreferenceManager. getDefaultSharedPreferences this;
Editor editor = prefs.edit; editor.putString“selection”, “JellyBean”: editor.putInt“year”,2012: editor.apply;
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Accessing Files
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 Internal File System  Real file system mounted under Linux.  All the usual Java file I/O routines from java.io package are available.  Only can access a package private directory /data/data/package name/files/  Users of rooted devices will be able to access all the files in Internal File System
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InputStream is = openFileInput"notes.txt"; if is != null InputStreamReader isr = new InputStreamReaderis; BufferedReader reader = new BufferedReaderisr; String line; StringBuilder sb = new StringBuilder; while line = reader.readLine != null sb.appendstr + "\n"; is.close; editTextEditor.setTextsb.toString;  openFileInput - open the file
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OutputStreamWriter out = new OutputStreamWriteropenFileOutput"notes.txt", Context.MODE_PRIVATE; out.writeeditTextEditor.getText.toString; out.close;  openFileOutput - replace a file
 openFileOutput - append to a file OutputStreamWriter out = new OutputStreamWriteropenFileOutput"notes.txt", Context.MODE_APPEND; out.writeeditTextEditor.getText.toString; out.close;
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URL url = new URL"some image file url"; InputStream is = InputStreamurl.getContent; Bitmap bitmap = BitmapFactory.decodeStreamis; String imgString = getFilesDir + "/filename.png"; FileOutputStream fos = new FileOutputStreamimgString; bitmap.compressCompressFormat.PNG, 100, fos;  Save an image file to Internal Storage
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 Checking the internal file in the AVD by pulling the file out from /data/data/package_name/files in DDMS and view it via a desktop application
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 Files on External Storage SD Cards  Much larger than built-in memory- storing music and video files.  Every application can read and write files everywhere on SD Cards.  Both read and write files require permission.
uses-permission android:name = "android.permission.WRITE_EXTERNAL_STORAGE" / uses-permission android:name = "android.permission.READ_EXTERNAL_STORAGE" /
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File folder = Environment.getExternalStorageDirectory; String path = folder.getAbsolutePath + ”/notes.txt"; FileReader fr = new FileReaderpath; BufferedReader reader = new BufferedReaderfr; String line; StringBuilder sb = new StringBuilder; while line = reader.readLine != null sb.appendstr+"\n"; editTextEditor.setTextsb.toString; fr.close;  FileReader - open the file
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