* Tips: This function of iPhone is only effective for built-in music, and third-party music players such as cool dog and QQ music don't work. Don't ask Bian Xiao why, Bian Xiao can only say that Apple can protect itself! Set the iPhone's built-in player to automatically stop playing. Step: 1. First turn on the iPhone's clock, and then click "Timer" on the far right, which has an option of "Start when the timer ends". 2. Then you will see the screen for selecting the timer ringtone. At this time, just pull down to the bottom and select "Stop Running". 3. Then return to the timer page and set the time. The iPhone will automatically stop the music after the countdown and let the phone close the screen.