diff --git a/README.md b/README.md
index 35b4046..2e81ba6 100755
--- a/README.md
+++ b/README.md
@@ -86,8 +86,8 @@ The document is being written, please refer to the example source code.
 
 ## Overlay
 ![](https://github.com/rilyu/teaset/blob/master/screenshots/15-Overlay1.png?raw=true) ![](https://github.com/rilyu/teaset/blob/master/screenshots/15-Overlay2.png?raw=true)
-![](https://github.com/rilyu/teaset/blob/master/screenshots/15-Overlay3.png?raw=true) ![](https://github.com/rilyu/teaset/blob/master/screenshots/15-Overlay4.png?raw=true)
-![](https://github.com/rilyu/teaset/blob/master/screenshots/15-Overlay5.png?raw=true)
+![](https://github.com/rilyu/teaset/blob/master/screenshots/15-Overlay3.png?raw=true) ![](https://github.com/rilyu/teaset/blob/master/screenshots/15-Overlay6.png?raw=true)
+![](https://github.com/rilyu/teaset/blob/master/screenshots/15-Overlay4.png?raw=true) ![](https://github.com/rilyu/teaset/blob/master/screenshots/15-Overlay5.png?raw=true)
 
 ## Toast
 ![](https://github.com/rilyu/teaset/blob/master/screenshots/16-Toast1.png?raw=true) ![](https://github.com/rilyu/teaset/blob/master/screenshots/16-Toast2.png?raw=true)
diff --git a/components/NavigationBar/NavigationBar.js b/components/NavigationBar/NavigationBar.js
index e049bed..0ff2f22 100644
--- a/components/NavigationBar/NavigationBar.js
+++ b/components/NavigationBar/NavigationBar.js
@@ -3,7 +3,7 @@
 'use strict';
 
 import React, {Component, PropTypes} from 'react';
-import {StyleSheet, Platform, StatusBar, View, Text} from 'react-native';
+import {StyleSheet, Platform, StatusBar, View, Text, Animated} from 'react-native';
 
 import Theme from 'teaset/themes/Theme';
 import NavigationTitle from './NavigationTitle';
@@ -22,6 +22,8 @@ export default class NavigationBar extends Component {
     leftView: PropTypes.element,
     rightView: PropTypes.element,
     tintColor: PropTypes.string, //bar tint color, default tint color leftView and rightView
+    hidden: PropTypes.bool, //bar hidden
+    animated: PropTypes.bool, //hide or show bar with animation
     statusBarStyle: PropTypes.oneOf(['default', 'light-content']), //status bar style (iOS only)
     statusBarColor: PropTypes.string, //status bar color, default: style.backgroundColor
     statusBarHidden: PropTypes.bool, //status bar hidden
@@ -31,6 +33,8 @@ export default class NavigationBar extends Component {
   static defaultProps = {
     ...View.defaultProps,
     type: 'ios',
+    hidden: false,
+    animated: true,
     statusBarInsets: true,
   };
 
@@ -49,15 +53,23 @@ export default class NavigationBar extends Component {
     this.state = {
       leftViewWidth: 0,
       rightViewWidth: 0,
+      barTop: new Animated.Value(props.hidden ? -64 : 0),
+      barOpacity: new Animated.Value(props.hidden ? 0 : 1),
     };
   }
 
+  componentWillReceiveProps(nextProps) {
+    if (nextProps.hidden != this.props.hidden) {
+      this.checkBarHidden(nextProps.hidden, nextProps.animated);
+    }
+  }
+
   getChildContext() {
     return {tintColor: this.props.tintColor};
   }
 
   buildProps() {
-    let {style, type, title, titleStyle, tintColor, statusBarColor, statusBarStyle, statusBarInsets, ...others} = this.props;
+    let {style, type, title, titleStyle, tintColor, hidden, animated, statusBarColor, statusBarStyle, statusBarInsets, ...others} = this.props;
 
     //build style
     let justifyContent, titleTextAlign;
@@ -74,7 +86,6 @@ export default class NavigationBar extends Component {
     style = [{
       backgroundColor: Theme.navColor,
       position: 'absolute',
-      top: 0,
       left: 0,
       right: 0,
       height: statusBarInsets && Platform.OS === 'ios' ? 64 : 44,
@@ -86,7 +97,9 @@ export default class NavigationBar extends Component {
       flexDirection: 'row',
       alignItems: 'center',
       justifyContent: justifyContent,
-    }].concat(style);
+    }].concat(style).concat({
+      top: this.state.barTop, //hidden or shown
+    });
 
     let fs = StyleSheet.flatten(style);
 
@@ -121,17 +134,46 @@ export default class NavigationBar extends Component {
       height: 44,
       paddingLeft: paddingLeft,
       paddingRight: paddingRight,
+      opacity: this.state.barOpacity,
       flexDirection: 'row',
       alignItems: 'center',
       justifyContent: 'center',
-    }
+    };
+
+    //build leftView and rightView style
+    let leftRightViewStyle = {opacity: this.state.barOpacity};
 
     //convert string title to NavigationBar.Title
     if (typeof title === 'string') {
       title = <this.constructor.Title style={{textAlign: titleTextAlign, color: Theme.navTitleColor}} text={title} />;
     }
 
-    this.props = {style, type, title, titleStyle, tintColor, titleViewStyle, statusBarColor, statusBarStyle, statusBarInsets, ...others};
+    this.props = {style, type, title, titleStyle, tintColor, titleViewStyle, leftRightViewStyle, hidden, animated, statusBarColor, statusBarStyle, statusBarInsets, ...others};
+  }
+
+  checkBarHidden(hidden, animated) {
+    let {barTop, barOpacity} = this.state;
+    let barTopValue = hidden ? -this.barHeight : 0;
+    let barOpacityValue = hidden ? 0 : 1;
+    if (barTop._value != barTopValue || barOpacity._value != barOpacityValue) {
+      if (animated) {
+        Animated.parallel([
+          Animated.spring(barTop, {toValue: barTopValue, friction: 9}),
+          Animated.spring(barOpacity, {toValue: barOpacityValue, friction: 9}),
+        ]).start();
+      } else {
+        barTop.setValue(barTopValue);
+        barOpacity.setValue(barOpacityValue);
+      }      
+    }
+  }
+
+  onLayout(e) {
+    if (e.nativeEvent.layout.height != this.barHeight) {
+      this.barHeight = e.nativeEvent.layout.height;
+      this.checkBarHidden(this.props.hidden, this.props.animated);
+    }
+    this.props.onLayout && this.props.onLayout(e);
   }
 
   onLeftViewLayout(e) {
@@ -149,17 +191,14 @@ export default class NavigationBar extends Component {
   render() {
     this.buildProps();
 
-    let {style, statusBarStyle, statusBarColor, statusBarHidden, title, titleViewStyle, leftView, rightView, ...others} = this.props;
-    if (statusBarHidden) return (
-      <StatusBar backgroundColor={statusBarColor} barStyle={statusBarStyle} animated={true} hidden={statusBarHidden} />
-    );
+    let {style, animated, statusBarStyle, statusBarColor, statusBarHidden, title, titleViewStyle, leftRightViewStyle, leftView, rightView, ...others} = this.props;
     return (
-      <View style={style} {...others}>
-        <StatusBar backgroundColor={statusBarColor} barStyle={statusBarStyle} animated={true} hidden={statusBarHidden} />
-        <View style={titleViewStyle}>{title}</View>
-        <View onLayout={(e) => this.onLeftViewLayout(e)}>{leftView}</View>
-        <View onLayout={(e) => this.onRightViewLayout(e)}>{rightView}</View>
-      </View>
+      <Animated.View style={style} {...others} onLayout={e => this.onLayout(e)}>
+        <StatusBar backgroundColor={statusBarColor} barStyle={statusBarStyle} animated={animated} hidden={statusBarHidden} />
+        <Animated.View style={titleViewStyle}>{title}</Animated.View>
+        <Animated.View style={leftRightViewStyle} onLayout={e => this.onLeftViewLayout(e)}>{leftView}</Animated.View>
+        <Animated.View style={leftRightViewStyle} onLayout={e => this.onRightViewLayout(e)}>{rightView}</Animated.View>
+      </Animated.View>
     );
   }
 }
diff --git a/components/NavigationPage/NavigationPage.js b/components/NavigationPage/NavigationPage.js
index 5d659cc..c18a44d 100644
--- a/components/NavigationPage/NavigationPage.js
+++ b/components/NavigationPage/NavigationPage.js
@@ -16,6 +16,7 @@ export default class NavigationPage extends BasePage {
     ...BasePage.propTypes,
     title: PropTypes.string,
     showBackButton: PropTypes.bool,
+    navigationBarInsets: PropTypes.bool,
   };
 
   static defaultProps = {
@@ -23,18 +24,19 @@ export default class NavigationPage extends BasePage {
     scene: Navigator.SceneConfigs.PushFromRight,
     title: null,
     showBackButton: false,
+    navigationBarInsets: true,
   };
 
   buildProps() {
     super.buildProps();
 
-    let {...others} = this.props;
+    let {navigationBarInsets, ...others} = this.props;
     let pageContainerStyle = [{
       flex: 1,
       padding: 0,
-      marginTop: Platform.OS === 'ios' ? 64 : 44,
+      marginTop: navigationBarInsets ? (Platform.OS === 'ios' ? 64 : 44) : 0,
     }];
-    this.props = {pageContainerStyle, ...others};
+    this.props = {navigationBarInsets, pageContainerStyle, ...others};
   }
 
   renderNavigationTitle() {
diff --git a/components/Overlay/OverlayPullView.js b/components/Overlay/OverlayPullView.js
index 27acb48..9126cd5 100644
--- a/components/Overlay/OverlayPullView.js
+++ b/components/Overlay/OverlayPullView.js
@@ -15,7 +15,7 @@ export default class OverlayPullView extends OverlayView {
     ...OverlayView.propTypes,
     side: PropTypes.oneOf(['top', 'bottom', 'left', 'right']),
     containerStyle: View.propTypes.style,
-    rootTransform: PropTypes.oneOfType(
+    rootTransform: PropTypes.oneOfType([
       PropTypes.oneOf(['none', 'translate', 'scale']),
       PropTypes.arrayOf(PropTypes.shape({
         translateX: PropTypes.number,
@@ -23,7 +23,7 @@ export default class OverlayPullView extends OverlayView {
         scaleX: PropTypes.number,
         scaleY: PropTypes.number,
       })),
-    ),
+    ]),
   };
 
   static defaultProps = {
diff --git a/docs/cn/NavigationBar.md b/docs/cn/NavigationBar.md
index 888badc..5ca4c86 100644
--- a/docs/cn/NavigationBar.md
+++ b/docs/cn/NavigationBar.md
@@ -11,6 +11,8 @@ NavigationBar 组件定义一个页面导航条, 用于页面顶部显示页面
 | leftView | element |  | 导航条左视图。
 | rightView | element |  | 导航条右视图。
 | tintColor | string |  | 导航条左、右视图文字与图像颜色, 默认值在 Theme 中设置。
+| hidden | bool | false | 是否隐藏导航条
+| animated | bool | true | 显示/隐藏导航条和状态栏时是否有动画效果
 | statusBarStyle | string | 'default' | 系统状态栏样式(iOS only)。<br/>- default: 默认, 黑色文字或图标。<br/>- light-content: 亮色调, 白色文字或图标。
 | statusBarColor | string |  | 导航条背景颜色, 默认值在 Theme 中设置。
 | statusBarHidden | bool | false | 是否隐藏系统状态栏, 为 true 时系统状态栏与导航条均不显示。
diff --git a/docs/cn/NavigationPage.md b/docs/cn/NavigationPage.md
index 8d5840c..6e89b33 100644
--- a/docs/cn/NavigationPage.md
+++ b/docs/cn/NavigationPage.md
@@ -7,6 +7,7 @@ NavigationPage 定义一个导航页面组件, 继承自 [BasePage](./BasePage.m
 | [BasePage props...](./BasePage.md) |  |  | NavigationPage 组件继承 BasePage 组件的全部属性。
 | title | string | null | 导航条标题。
 | showBackButton | bool | false | 是否显示返回按钮。
+| navigationBarInsets | bool | true | 是否为内容区域增加导航条占用空间。<br/>此属性默认为 true, 使得内容不被导航条遮挡, 如果页面内容实用 ScrollView 且需要自行控制 NavigationBar 导航条的显示/隐藏, 那么你需要将此属性设置为 false 并自行在 ScrollView 容器里增加导航条的占用空间, 这样可以在导航条隐藏后把顶部空间利用起来。
 | scene | object | Navigator.SceneConfigs.PushFromRight | 继承自 BasePage 并修改默认值。
 
 ## Methods
diff --git a/example/views/NavigationBarExample.js b/example/views/NavigationBarExample.js
index 5e0fd56..2bcd4c0 100644
--- a/example/views/NavigationBarExample.js
+++ b/example/views/NavigationBarExample.js
@@ -3,99 +3,260 @@
 'use strict';
 
 import React, {Component, PropTypes} from 'react';
-import {View, ScrollView} from 'react-native';
+import {Platform, View, ScrollView, Switch} from 'react-native';
 
-import {NavigationPage, ListRow, NavigationBar, Label} from 'teaset';
+import {Theme, NavigationPage, ListRow, NavigationBar, Label, Select} from 'teaset';
 
 export default class NavigationBarExample extends NavigationPage {
 
   static defaultProps = {
     ...NavigationPage.defaultProps,
     title: 'NavigationBar',
-    showBackButton: true,
+    navigationBarInsets: false,
   };
 
-  renderHeader(text) {
-    return (
-      <View style={{paddingLeft: 8, paddingTop: 16, paddingBottom: 8}}>
-        <Label style={{fontSize: 15}} type='detail' text={text} />
-      </View>
-    );
+  constructor(props) {
+    super(props);
+
+    this.typeItems = ['Auto', 'iOS', 'Android'];
+    this.titleItems = ['String', 'Custom'];
+    this.leftViewItems = ['None', 'Back button', 'Link button', 'Icon button', 'Two icon button'];
+    this.rightViewItems = ['None', 'Link button', 'Icon button', 'Two icon button'];
+    this.bgColorItems = ['Default', 'Custom'];
+    this.tintColorItems = ['Default', 'Custom'];
+    this.statusBarStyleItems = ['Default', 'Light Content'];
+
+    Object.assign(this.state, {
+      type: 'iOS',
+      title: 'String',
+      leftView: 'Back button',
+      rightView: 'None',
+      bgColor: 'Default',
+      tintColor: 'Default',
+      hidden: false,
+      animated: true,
+      statusBarStyle: 'Light Content',
+      statusBarHidden: false,
+    });
+  }
+
+  get type() {
+    switch (this.state.type) {
+      case 'Auto': return Platform.OS;
+      default: return this.state.type.toLowerCase();
+    }
   }
 
-  renderDetail(type, example) {
-    let title = example, leftView, rightView;
-    let style = {
-      //only for this example, do not use in your code
-      flex: 1,
-      position: 'relative',
-    };
-    let tintColor;
-    switch (example) {
-      case 'Default':
-        rightView = (
+  get style() {
+    switch (this.state.bgColor) {
+      case 'Default': return null;
+      case 'Custom': return {backgroundColor: '#e75f35'};
+    }
+  }
+
+  get tintColor() {
+    switch(this.state.tintColor) {
+      case 'Default': return null;
+      case 'Custom': return '#3af455';
+    }
+  }
+
+  get statusBarStyle() {
+    switch(this.state.statusBarStyle) {
+      case 'Default': return 'default';
+      case 'Light Content': return 'light-content';
+    }
+  }
+
+  renderLeftRightView(item) {
+    switch (item) {
+      case 'None':
+        return null;
+      case 'Back button':
+        return (
+          <NavigationBar.BackButton
+            title={Theme.backButtonTitle}
+            onPress={() => this.navigator.pop()}
+            />
+        );
+      case 'Link button':
+        return (
+          <NavigationBar.LinkButton title='Link' />
+        );
+      case 'Icon button':
+        return (
           <NavigationBar.IconButton icon={require('../icons/search.png')} />
         );
-        break;
+      case 'Two icon button':
+        return (
+          <View style={{flexDirection: 'row'}}>
+            <NavigationBar.IconButton icon={require('../icons/edit.png')} />
+            <NavigationBar.IconButton icon={require('../icons/trash.png')} />
+          </View>
+        );
+    }
+  }
+
+  renderNavigationTitle() {
+    let {title} = this.state;
+    switch (title) {
+      case 'String':
+        return this.props.title;
       case 'Custom':
         let titleStyle = {
           flex: 1,
           paddingLeft: 4,
           paddingRight: 4,
-          alignItems: type === 'ios' ? 'center' : 'flex-start',
+          alignItems: this.type === 'ios' ? 'center' : 'flex-start',
         };
-        style.backgroundColor = '#eff';
-        tintColor = '#333';
-        title = (
+        return (
           <View style={titleStyle}>
-            <Label style={{color: '#000', fontSize: 15}} text={title} />
-            <Label style={{color: '#333', fontSize: 11}}  text='Secondary title' />
+            <Label style={{color: Theme.navTitleColor, fontSize: 15}} text='Title' />
+            <Label style={{color: Theme.navTitleColor, fontSize: 11}}  text='Secondary title' />
           </View>
         );
-        leftView = (
-          <NavigationBar.IconButton icon={require('../icons/search.png')} />
-        );
-        rightView = (
-          <View style={{flexDirection: 'row'}}>
-            <NavigationBar.IconButton icon={require('../icons/edit.png')} />
-            <NavigationBar.IconButton icon={require('../icons/trash.png')} />
-          </View>
-        );
-        break;
-      case 'Back Button':
-        leftView = <NavigationBar.BackButton title='Back' />;
-        break;
-      case 'Link Button':
-        leftView = <NavigationBar.LinkButton title='Close' />;
-        rightView = <NavigationBar.LinkButton title='OK' />;
-        break;
     }
+  }
+
+  renderNavigationLeftView() {
+    return this.renderLeftRightView(this.state.leftView);
+  }
+
+  renderNavigationRightView() {
+    return this.renderLeftRightView(this.state.rightView);
+  }
+
+  renderNavigationBar() {
+    let {hidden, animated, statusBarHidden} = this.state;
     return (
       <NavigationBar
-        style={style}
-        type={type}
-        tintColor={tintColor}
-        title={title}
-        leftView={leftView}
-        rightView={rightView}
+        style={this.style}
+        type={this.type}
+        title={this.renderNavigationTitle()}
+        leftView={this.renderNavigationLeftView()}
+        rightView={this.renderNavigationRightView()}
+        tintColor={this.tintColor}
+        hidden={hidden}
+        animated={animated}
+        statusBarStyle={this.statusBarStyle}
+        statusBarHidden={statusBarHidden}
         />
     );
   }
 
   renderPage() {
+    let {type, title, leftView, rightView, bgColor, tintColor, hidden, animated, statusBarStyle, statusBarHidden} = this.state;
     return (
       <ScrollView style={{flex: 1}}>
-        {this.renderHeader('Android')}
-        <ListRow titlePlace='none' detail={this.renderDetail('android', 'Default')} topSeparator='full' />
-        <ListRow titlePlace='none' detail={this.renderDetail('android', 'Custom')} bottomSeparator='full' />
-        {this.renderHeader('iOS')}
-        <ListRow titlePlace='none' detail={this.renderDetail('ios', 'Default')} topSeparator='full' />
-        <ListRow titlePlace='none' detail={this.renderDetail('ios', 'Custom')} />
-        <ListRow titlePlace='none' detail={this.renderDetail('ios', 'Back Button')} bottomSeparator='full' />
-        {this.renderHeader('Auto')}
-        <ListRow titlePlace='none' detail={this.renderDetail('auto', 'Link Button')} topSeparator='full' bottomSeparator='full' />
+        <View style={{height: Platform.OS === 'ios' ? 64 : 44, alignItems: 'center', justifyContent: 'center'}}>
+          <Label style={{color: '#ccc'}} size='xl' text='ScrollView header' />
+        </View>
+        <View style={{height: 20}} />
+        <SelectRow
+          title='Type'
+          value={type}
+          items={this.typeItems}
+          onSelected={(item, index) => this.setState({type: item})}
+          topSeparator='full'
+          />
+        <SelectRow
+          title='Title'
+          value={title}
+          items={this.titleItems}
+          onSelected={(item, index) => this.setState({title: item})}
+          />
+        <SelectRow
+          title='Left view'
+          value={leftView}
+          items={this.leftViewItems}
+          onSelected={(item, index) => this.setState({leftView: item})}
+          />
+        <SelectRow
+          title='Right view'
+          value={rightView}
+          items={this.rightViewItems}
+          onSelected={(item, index) => this.setState({rightView: item})}
+          />
+        <SelectRow
+          title='Background color'
+          value={bgColor}
+          items={this.bgColorItems}
+          onSelected={(item, index) => this.setState({bgColor: item})}
+          />
+        <SelectRow
+          title='Tint color'
+          value={tintColor}
+          items={this.tintColorItems}
+          onSelected={(item, index) => this.setState({tintColor: item})}
+          />
+        <ListRow
+          title='Hidden'
+          detail={<Switch value={hidden} onValueChange={value => this.setState({hidden: value})} />}
+          />
+        <ListRow
+          title='Animated'
+          detail={<Switch value={animated} onValueChange={value => this.setState({animated: value})} />}
+          bottomSeparator='full'
+          />
+        <View style={{height: 20}} />
+        <SelectRow
+          title='Status bar style (iOS)'
+          value={statusBarStyle}
+          items={this.statusBarStyleItems}
+          onSelected={(item, index) => this.setState({statusBarStyle: item})}
+          topSeparator='full'
+          />
+        <ListRow
+          title='Status bar hidden'
+          detail={<Switch value={statusBarHidden} onValueChange={value => this.setState({statusBarHidden: value})} />}
+          bottomSeparator='full'
+          />
       </ScrollView>
     );
   }
 
 }
+
+class SelectRow extends ListRow {
+
+  static propTypes = {
+    ...ListRow.propTypes,
+    value: PropTypes.any,
+    items: PropTypes.array,
+    getItemValue: PropTypes.func,
+    getItemText: PropTypes.func,
+    emptyText: PropTypes.string,
+    emptyTextColor: PropTypes.string,
+    onSelected: PropTypes.func.isRequired,
+  };
+
+  static defaultProps = {
+    ...ListRow.defaultProps,
+    emptyText: 'Select item',
+    emptyTextColor: '#ff8f99',
+  };
+
+  buildProps() {
+    let {title, detail, value, items, getItemValue, getItemText, emptyText, emptyTextColor, onSelected, ...others} = this.props;
+    detail = (
+      <Select
+        style={{borderWidth: 0, flex: 1}}
+        value={value}
+        valueStyle={{textAlign: 'right'}}
+        items={items}
+        getItemValue={getItemValue}
+        getItemText={getItemText}
+        editable={items && items.length > 0}
+        placeholder={emptyText}
+        placeholderTextColor={emptyTextColor}
+        pickerTitle={typeof title === 'string' ? title : null}
+        onSelected={(item, index) => onSelected && onSelected(items[index], index)}
+        />
+    );
+
+    this.props = {title, detail, value, items, getItemValue, getItemText, emptyText, emptyTextColor, onSelected, ...others};
+
+    super.buildProps();
+  }
+
+}
diff --git a/package.json b/package.json
index 1147d63..fff316a 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "teaset",
-  "version": "0.1.3",
+  "version": "0.1.4",
   "description": "A UI library for react native.",
   "main": "index.js",
   "scripts": {