调整vip在ios 上文字有背景色的问题。review by 孙凯。

@@ -36,7 +36,7 @@ export default class Birth extends Component {
 
                 <TouchableOpacity style={styles.getCouponContainer} activeOpacity={1} onPress={() => { this.props.onPressGetCoupon && this.props.onPressGetCoupon()}}>
                     <Text style={styles.getCouponText}>立即领取生日福利券</Text>
-                </TouchableOpacity>                 
+                </TouchableOpacity>
 
                 <View style={styles.tipContainer}>
 
@@ -82,12 +82,12 @@ export default class Birth extends Component {
                 <Text style={styles.tipBottomMsg}>温馨提示：同一用户一年内（365天）仅可领取一次生日特惠哦！</Text>
 
                 {
-                    showAlert ? 
-                        <CouponAlertView 
+                    showAlert ?
+                        <CouponAlertView
                             notSupportReasons={notSupportReasons}
                             notSupportReasonsTitle={notSupportReasonsTitle}
                             notSupportReasonsMessage={notSupportReasonsMessage}
-                            onPressClose={this.props.onPressClose} /> 
+                            onPressClose={this.props.onPressClose} />
                     : null
                 }
 
@@ -98,6 +98,7 @@ export default class Birth extends Component {
 
 let {width, height} = Dimensions.get('window');
 const DEVICE_WIDTH_RATIO = width / 320;
+const radio = 942 / 640;
 
 
 let styles = StyleSheet.create({
@@ -108,13 +109,16 @@ let styles = StyleSheet.create({
 
     contentBg: {
         width: width,
-        height: 471 * DEVICE_WIDTH_RATIO,
+        height: Math.ceil(width*radio),
     },
 
     getCouponContainer:{
         position: 'absolute',
-        top: 250 * DEVICE_WIDTH_RATIO,
-        left: 76 * DEVICE_WIDTH_RATIO,
+        width: width,
+        top: Math.ceil(width*radio*(525 / 942)) - (Platform.OS === 'ios'? 10 : 15),
+        alignItems: 'center',
+        justifyContent: 'center',
+        backgroundColor: 'transparent',
     },
 
     getCouponText:{
@@ -139,6 +143,7 @@ let styles = StyleSheet.create({
         color: '#ffffff',
         fontWeight: 'bold',
         fontStyle: 'italic',
+        backgroundColor: 'transparent',
     },
 
     tipContentContainer:{