[self.shareButton mas_updateConstraints:^(MASConstraintMaker *make) {
make.top.equalTo(self.qrcodeLabel.mas_bottom).with.offset(20);
make.centerX.equalTo(self.view);
make.size.mas_equalTo(CGSizeMake(120, 40));
}];
[self.shareButton mas_updateConstraints:^(MASConstraintMaker *make) {
make.top.equalTo(self.qrcodeLabel.mas_bottom).with.offset(20);
make.centerX.equalTo(self.view);
make.size.mas_equalTo(CGSizeMake(120, 40));
}];