##Overview A Demo for CAEmitterLayer and CAEmitterCell
一个关于CAEmitterLayer和CAEmitterCell的Demo
#import "LWWeatherBackgroundView.h"
//1.init the LWWeatherBackgroundView
self.weatherBackgroundView = [[LWWeatherBackgroundView alloc] initWithFrame:self.view.bounds];
//Or you can set the frame later
// self.weatherBackgroundView = [[LWWeatherBackgroundView alloc] init];
// self.weatherBackgroundView.frame = CGRectMake(0, 20, self.view.bounds.size.width, 500);
//2.set/change the weatherModel
[self.weatherBackgroundView setWeatherCellModel:WeatherCellModeRain];
[self.view addSubview:self.weatherBackgroundView];
//3.send the LWWeatherBackgroundView to back
[self.view sendSubviewToBack:self.weatherBackgroundView];