iOS基础-播放暂停按钮

[btn setImage:[UIImage imageWithName:@"paly"] forState:UIControlStateNormal];

　　

[btn addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];

　　

- (void)btnClick:(UIButton *)btn{
     if(btn.tag == -1){
      [btn setImage:[UIImage imageWithName:@"paly"] forState:UIControlStateNomal];
      NSLog(@"开始播放");
      btn.tag = 0;
      }else{
      [btn setImage:[UIImage imageWithName:@"pause"] forState:UIControlStateNomal];
      NSLog(@"暂停播放");
      btn.tag = -1;
      }
}

　　

取出当前软件版本号的方法

//上一次使用软件的版本号
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString *lastVersion = [deafults stringForKey:@"versionCode"];

//当前软件版本号
NSString *currentVersion = [NSBundle mainBundle].infoDictionary[@"CGBundleVersion"];
//获取版本号后即存入NSUserDefaults
[defaults setObject:currentVersion forKey:@"lastVersion"];
[defaults synchronize];