Christopher Tate | 38507bb | 2011-03-11 12:39:17 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2011 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.hugebackup; |
| 18 | |
| 19 | import android.app.Activity; |
| 20 | import android.app.backup.BackupManager; |
| 21 | import android.app.backup.RestoreObserver; |
| 22 | import android.os.Bundle; |
| 23 | import android.util.Log; |
| 24 | import android.view.View; |
| 25 | import android.widget.CheckBox; |
| 26 | import android.widget.CompoundButton; |
| 27 | import android.widget.RadioGroup; |
| 28 | |
| 29 | import java.io.File; |
| 30 | import java.io.IOException; |
| 31 | import java.io.RandomAccessFile; |
| 32 | |
| 33 | /** |
| 34 | * Deliberately back up waaaaaaay too much data. Cloned with some alterations |
| 35 | * from the Backup/Restore sample application. |
| 36 | */ |
| 37 | public class HugeBackupActivity extends Activity { |
| 38 | static final String TAG = "HugeBackupActivity"; |
| 39 | |
| 40 | /** |
| 41 | * We serialize access to our persistent data through a global static |
| 42 | * object. This ensures that in the unlikely event of the our backup/restore |
| 43 | * agent running to perform a backup while our UI is updating the file, the |
| 44 | * agent will not accidentally read partially-written data. |
| 45 | * |
| 46 | * <p>Curious but true: a zero-length array is slightly lighter-weight than |
| 47 | * merely allocating an Object, and can still be synchronized on. |
| 48 | */ |
| 49 | static final Object[] sDataLock = new Object[0]; |
| 50 | |
| 51 | /** Also supply a global standard file name for everyone to use */ |
| 52 | static final String DATA_FILE_NAME = "saved_data"; |
| 53 | |
| 54 | /** The various bits of UI that the user can manipulate */ |
| 55 | RadioGroup mFillingGroup; |
| 56 | CheckBox mAddMayoCheckbox; |
| 57 | CheckBox mAddTomatoCheckbox; |
| 58 | |
| 59 | /** Cache a reference to our persistent data file */ |
| 60 | File mDataFile; |
| 61 | |
| 62 | /** Also cache a reference to the Backup Manager */ |
| 63 | BackupManager mBackupManager; |
| 64 | |
| 65 | /** Set up the activity and populate its UI from the persistent data. */ |
| 66 | @Override |
| 67 | public void onCreate(Bundle savedInstanceState) { |
| 68 | super.onCreate(savedInstanceState); |
| 69 | |
| 70 | /** Establish the activity's UI */ |
| 71 | setContentView(R.layout.backup_restore); |
| 72 | |
| 73 | /** Once the UI has been inflated, cache the controls for later */ |
Alan Viverette | 51efddb | 2017-04-05 10:00:01 -0400 | [diff] [blame] | 74 | mFillingGroup = findViewById(R.id.filling_group); |
| 75 | mAddMayoCheckbox = findViewById(R.id.mayo); |
| 76 | mAddTomatoCheckbox = findViewById(R.id.tomato); |
Christopher Tate | 38507bb | 2011-03-11 12:39:17 -0800 | [diff] [blame] | 77 | |
| 78 | /** Set up our file bookkeeping */ |
| 79 | mDataFile = new File(getFilesDir(), HugeBackupActivity.DATA_FILE_NAME); |
| 80 | |
| 81 | /** It is handy to keep a BackupManager cached */ |
| 82 | mBackupManager = new BackupManager(this); |
| 83 | |
| 84 | /** |
| 85 | * Finally, build the UI from the persistent store |
| 86 | */ |
| 87 | populateUI(); |
| 88 | } |
| 89 | |
| 90 | /** |
| 91 | * Configure the UI based on our persistent data, creating the |
| 92 | * data file and establishing defaults if necessary. |
| 93 | */ |
| 94 | void populateUI() { |
| 95 | RandomAccessFile file; |
| 96 | |
| 97 | // Default values in case there's no data file yet |
| 98 | int whichFilling = R.id.pastrami; |
| 99 | boolean addMayo = false; |
| 100 | boolean addTomato = false; |
| 101 | |
| 102 | /** Hold the data-access lock around access to the file */ |
| 103 | synchronized (HugeBackupActivity.sDataLock) { |
| 104 | boolean exists = mDataFile.exists(); |
| 105 | try { |
| 106 | file = new RandomAccessFile(mDataFile, "rw"); |
| 107 | if (exists) { |
| 108 | Log.v(TAG, "datafile exists"); |
| 109 | whichFilling = file.readInt(); |
| 110 | addMayo = file.readBoolean(); |
| 111 | addTomato = file.readBoolean(); |
| 112 | Log.v(TAG, " mayo=" + addMayo |
| 113 | + " tomato=" + addTomato |
| 114 | + " filling=" + whichFilling); |
| 115 | } else { |
| 116 | // The default values were configured above: write them |
| 117 | // to the newly-created file. |
| 118 | Log.v(TAG, "creating default datafile"); |
| 119 | writeDataToFileLocked(file, |
| 120 | addMayo, addTomato, whichFilling); |
| 121 | |
| 122 | // We also need to perform an initial backup; ask for one |
| 123 | mBackupManager.dataChanged(); |
| 124 | } |
| 125 | } catch (IOException ioe) { |
| 126 | } |
| 127 | } |
| 128 | |
| 129 | /** Now that we've processed the file, build the UI outside the lock */ |
| 130 | mFillingGroup.check(whichFilling); |
| 131 | mAddMayoCheckbox.setChecked(addMayo); |
| 132 | mAddTomatoCheckbox.setChecked(addTomato); |
| 133 | |
| 134 | /** |
| 135 | * We also want to record the new state when the user makes changes, |
| 136 | * so install simple observers that do this |
| 137 | */ |
| 138 | mFillingGroup.setOnCheckedChangeListener( |
| 139 | new RadioGroup.OnCheckedChangeListener() { |
| 140 | public void onCheckedChanged(RadioGroup group, |
| 141 | int checkedId) { |
| 142 | // As with the checkbox listeners, rewrite the |
| 143 | // entire state file |
| 144 | Log.v(TAG, "New radio item selected: " + checkedId); |
| 145 | recordNewUIState(); |
| 146 | } |
| 147 | }); |
| 148 | |
| 149 | CompoundButton.OnCheckedChangeListener checkListener |
| 150 | = new CompoundButton.OnCheckedChangeListener() { |
| 151 | public void onCheckedChanged(CompoundButton buttonView, |
| 152 | boolean isChecked) { |
| 153 | // Whichever one is altered, we rewrite the entire UI state |
| 154 | Log.v(TAG, "Checkbox toggled: " + buttonView); |
| 155 | recordNewUIState(); |
| 156 | } |
| 157 | }; |
| 158 | mAddMayoCheckbox.setOnCheckedChangeListener(checkListener); |
| 159 | mAddTomatoCheckbox.setOnCheckedChangeListener(checkListener); |
| 160 | } |
| 161 | |
| 162 | /** |
| 163 | * Handy helper routine to write the UI data to a file. |
| 164 | */ |
| 165 | void writeDataToFileLocked(RandomAccessFile file, |
| 166 | boolean addMayo, boolean addTomato, int whichFilling) |
| 167 | throws IOException { |
| 168 | file.setLength(0L); |
| 169 | file.writeInt(whichFilling); |
| 170 | file.writeBoolean(addMayo); |
| 171 | file.writeBoolean(addTomato); |
| 172 | Log.v(TAG, "NEW STATE: mayo=" + addMayo |
| 173 | + " tomato=" + addTomato |
| 174 | + " filling=" + whichFilling); |
| 175 | } |
| 176 | |
| 177 | /** |
| 178 | * Another helper; this one reads the current UI state and writes that |
| 179 | * to the persistent store, then tells the backup manager that we need |
| 180 | * a backup. |
| 181 | */ |
| 182 | void recordNewUIState() { |
| 183 | boolean addMayo = mAddMayoCheckbox.isChecked(); |
| 184 | boolean addTomato = mAddTomatoCheckbox.isChecked(); |
| 185 | int whichFilling = mFillingGroup.getCheckedRadioButtonId(); |
| 186 | try { |
| 187 | synchronized (HugeBackupActivity.sDataLock) { |
| 188 | RandomAccessFile file = new RandomAccessFile(mDataFile, "rw"); |
| 189 | writeDataToFileLocked(file, addMayo, addTomato, whichFilling); |
| 190 | } |
| 191 | } catch (IOException e) { |
| 192 | Log.e(TAG, "Unable to record new UI state"); |
| 193 | } |
| 194 | |
| 195 | mBackupManager.dataChanged(); |
| 196 | } |
| 197 | |
| 198 | /** |
| 199 | * Click handler, designated in the layout, that runs a restore of the app's |
| 200 | * most recent data when the button is pressed. |
| 201 | */ |
| 202 | public void onRestoreButtonClick(View v) { |
| 203 | Log.v(TAG, "Requesting restore of our most recent data"); |
| 204 | mBackupManager.requestRestore( |
| 205 | new RestoreObserver() { |
| 206 | public void restoreFinished(int error) { |
| 207 | /** Done with the restore! Now draw the new state of our data */ |
| 208 | Log.v(TAG, "Restore finished, error = " + error); |
| 209 | populateUI(); |
| 210 | } |
| 211 | } |
| 212 | ); |
| 213 | } |
| 214 | } |