Vibration.vibrate can't work before recordAsync

[teilala]

takePicture = async function() {
if (this.camera) {
if(this.state.recording==false)
{
Vibration.vibrate();//---->just only work at first time
this.setState({
takeIcon:'stop-circle-outline',
recording:true,
});
this.camera.recordAsync({"quality":"4:3","maxDuration":10}).then(data => {
Vibration.vibrate();//---->every time can work ,good boy.
});
}
else
{
this.camera.stopRecording();
this.setState({
takeIcon:'radiobox-marked',
recording:false,
});
}
}
};

but I try take picture with vibrate like the sample is work, so...why...I am ios