A wrapper class for the Android 2.2+ BackupHelper class. : BackupHelper « UI « Android

1. Android
2. UI
3. BackupHelper

A wrapper class for the Android 2.2+ BackupHelper class.

    
package com.sputnik.wispr.util;

import java.io.IOException;

import android.app.backup.BackupAgentHelper;
import android.app.backup.BackupDataInput;
import android.app.backup.BackupDataOutput;
import android.app.backup.SharedPreferencesBackupHelper;
import android.content.Context;
import android.os.ParcelFileDescriptor;
import android.util.Log;

/**
 * A wrapper class for the Android 2.2+ BackupHelper class. It marshalls all calls to the helper to
 * the original class, but only if it exists. Inspired on the official doc at
 * http://developer.android.com/resources/articles/backward-compatibility.html
 * 
 * @author erickok
 */
public class BackupAgentHelperWrapper extends BackupAgentHelper {
  private static String TAG = BackupAgentHelperWrapper.class.getName();

  private BackupAgentHelper instance = null;

  private static boolean checkAvailability = true;

  private static boolean isAvailable = false;

  /**
   * Class initialization which will fail when the helper class doesn't exist
   */
  static {
    if (checkAvailability) {
      try {
        Class.forName("android.app.backup.BackupAgentHelper");
        isAvailable = true;
      } catch (Exception e) {
        isAvailable = false;
      } finally {
        checkAvailability = false;
      }
      Log.d(TAG, "isAvailable:" + isAvailable);
    }
  }

  public BackupAgentHelperWrapper() {
    if (isAvailable) {
      instance = new BackupAgentHelper();
      Log.d(TAG, "instance:" + instance);
    }
  }

  protected Context getBackupAgentInstance() {
    Context ctx = null;
    if (isAvailable) {
      ctx = instance;
    }
    return ctx;
  }

  @Override
  public void onCreate() {
    if (isAvailable) {
      instance.onCreate();
    }
  }

  @Override
  public void onDestroy() {
    if (isAvailable) {
      instance.onDestroy();
    }
  }

  @Override
  public void onBackup(ParcelFileDescriptor oldState, BackupDataOutput data, ParcelFileDescriptor newState)
      throws IOException {
    if (isAvailable) {
      instance.onBackup(oldState, data, newState);
    }
  }

  @Override
  public void onRestore(BackupDataInput data, int appVersionCode, ParcelFileDescriptor newState) throws IOException {
    if (isAvailable) {
      instance.onRestore(data, appVersionCode, newState);
    }
  }

  public void addHelper(String keyPrefix, SharedPreferencesBackupHelper helper) {
    if (isAvailable) {
      instance.addHelper(keyPrefix, helper);
    }
  }

  @Override
  public String getPackageName() {
    String pkgName = null;
    if (isAvailable) {
      Log.d(TAG, "getPackageName@instance:" + instance);
      pkgName = instance.getPackageName();
    }
    return pkgName;
  }

}

   
    
    
    
  

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