Presistence

//
// ViewController.m
// Presistence
//
// Created by 张光发 on 15/11/11.
// Copyright © 2015年 张光发. All rights reserved.
//

import “ViewController.h”

@interface ViewController ()
@property(strong,nonatomic) IBOutletCollection(UITextField) NSArray *lineFields;
@end

@implementation ViewController

//获取data.plist文件完整路径
-(NSString *)dataFailePath
{
//获取Documents文件的路径
NSArray *path=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentDiectory=[path objectAtIndex:0];
//获取data.plist文件的完整路径
return [documentDiectory stringByAppendingPathExtension:@”data.plist”];
}

• (void)viewDidLoad {
  [super viewDidLoad];

  //获取完整路径
  NSString *filePath=[self dataFailePath];
  //确保文件存在
  if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
  //把文件中的内容加载到nsarray中
  NSArray *array=[[NSArray alloc] initWithContentsOfFile:filePath];
  //把nsarray中的内容恢复到输入框中
  for (int i=0; i<4; i++) {
  UITextField *theField=self.lineFields[i];
  theField.text=array[i];
  NSLog(@”%@”,array[i]);
  }
  }

  //订阅通知
  UIApplication *app=[UIApplication sharedApplication];
  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationWillResignActive:) name:UIApplicationWillResignActiveNotification object:app];
  }

//收到通知的回调方法
-(void)applicationWillResignActive:(NSNotification *)notification
{
NSLog(@”接收到通知”);
//获取文件路径
NSString *filePath=[self dataFailePath];
//把输入内容收集到nsarray
NSArray *array=[self.lineFields valueForKey:@”text”];
//把nsarray的内容写到文件中
//atomically设置为yes可以把内容先写到副本中，防止因为程序崩溃造成原来的文件损坏
[array writeToFile:filePath atomically:YES];
}

• (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }