forked from ptomasroos/react-native-scrollable-tab-view
-
Notifications
You must be signed in to change notification settings - Fork 0
/
ScrollableTabBar.js
241 lines (213 loc) · 7.58 KB
/
ScrollableTabBar.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
const React = require('react');
const { ViewPropTypes } = ReactNative = require('react-native');
const PropTypes = require('prop-types');
const createReactClass = require('create-react-class');
const {
View,
Animated,
StyleSheet,
ScrollView,
Text,
Platform,
Dimensions,
} = ReactNative;
const Button = require('./Button');
const WINDOW_WIDTH = Dimensions.get('window').width;
const ScrollableTabBar = createReactClass({
propTypes: {
goToPage: PropTypes.func,
activeTab: PropTypes.number,
tabs: PropTypes.array,
backgroundColor: PropTypes.string,
activeTextColor: PropTypes.string,
inactiveTextColor: PropTypes.string,
scrollOffset: PropTypes.number,
style: ViewPropTypes.style,
tabStyle: ViewPropTypes.style,
tabsContainerStyle: ViewPropTypes.style,
textStyle: Text.propTypes.style,
renderTab: PropTypes.func,
underlineStyle: ViewPropTypes.style,
onScroll: PropTypes.func,
},
getDefaultProps() {
return {
scrollOffset: 52,
activeTextColor: 'navy',
inactiveTextColor: 'black',
backgroundColor: null,
style: {},
tabStyle: {},
tabsContainerStyle: {},
underlineStyle: {},
};
},
getInitialState() {
this._tabsMeasurements = [];
return {
_leftTabUnderline: new Animated.Value(0),
_widthTabUnderline: new Animated.Value(0),
_containerWidth: null,
};
},
componentDidMount() {
this.props.scrollValue.addListener(this.updateView);
},
updateView(offset) {
const position = Math.floor(offset.value);
const pageOffset = offset.value % 1;
const tabCount = this.props.tabs.length;
const lastTabPosition = tabCount - 1;
if (tabCount === 0 || offset.value < 0 || offset.value > lastTabPosition) {
return;
}
if (this.necessarilyMeasurementsCompleted(position, position === lastTabPosition)) {
this.updateTabPanel(position, pageOffset);
this.updateTabUnderline(position, pageOffset, tabCount);
}
},
necessarilyMeasurementsCompleted(position, isLastTab) {
return this._tabsMeasurements[position] &&
(isLastTab || this._tabsMeasurements[position + 1]) &&
this._tabContainerMeasurements &&
this._containerMeasurements;
},
updateTabPanel(position, pageOffset) {
const containerWidth = this._containerMeasurements.width;
const tabWidth = this._tabsMeasurements[position].width;
const nextTabMeasurements = this._tabsMeasurements[position + 1];
const nextTabWidth = nextTabMeasurements && nextTabMeasurements.width || 0;
const tabOffset = this._tabsMeasurements[position].left;
const absolutePageOffset = pageOffset * tabWidth;
let newScrollX = tabOffset + absolutePageOffset;
// center tab and smooth tab change (for when tabWidth changes a lot between two tabs)
newScrollX -= (containerWidth - (1 - pageOffset) * tabWidth - pageOffset * nextTabWidth) / 2;
newScrollX = newScrollX >= 0 ? newScrollX : 0;
if (Platform.OS === 'android') {
this._scrollView.scrollTo({x: newScrollX, y: 0, animated: false, });
} else {
const rightBoundScroll = this._tabContainerMeasurements.width - (this._containerMeasurements.width);
newScrollX = newScrollX > rightBoundScroll ? rightBoundScroll : newScrollX;
this._scrollView.scrollTo({x: newScrollX, y: 0, animated: false, });
}
},
updateTabUnderline(position, pageOffset, tabCount) {
const lineLeft = this._tabsMeasurements[position].left;
const lineRight = this._tabsMeasurements[position].right;
if (position < tabCount - 1) {
const nextTabLeft = this._tabsMeasurements[position + 1].left;
const nextTabRight = this._tabsMeasurements[position + 1].right;
const newLineLeft = (pageOffset * nextTabLeft + (1 - pageOffset) * lineLeft);
const newLineRight = (pageOffset * nextTabRight + (1 - pageOffset) * lineRight);
this.state._leftTabUnderline.setValue(newLineLeft);
this.state._widthTabUnderline.setValue(newLineRight - newLineLeft);
} else {
this.state._leftTabUnderline.setValue(lineLeft);
this.state._widthTabUnderline.setValue(lineRight - lineLeft);
}
},
renderTab(name, page, isTabActive, onPressHandler, onLayoutHandler) {
const { activeTextColor, inactiveTextColor, textStyle, } = this.props;
const textColor = isTabActive ? activeTextColor : inactiveTextColor;
const fontWeight = isTabActive ? 'bold' : 'normal';
return <Button
key={`${name}_${page}`}
accessible={true}
accessibilityLabel={name}
accessibilityTraits='button'
onPress={() => onPressHandler(page)}
onLayout={onLayoutHandler}
>
<View style={[styles.tab, this.props.tabStyle, ]}>
<Text style={[{color: textColor, fontWeight, }, textStyle, ]}>
{name}
</Text>
</View>
</Button>;
},
measureTab(page, event) {
const { x, width, height, } = event.nativeEvent.layout;
this._tabsMeasurements[page] = {left: x, right: x + width, width, height, };
this.updateView({value: this.props.scrollValue.__getValue(), });
},
render() {
const tabUnderlineStyle = {
position: 'absolute',
height: 4,
backgroundColor: 'navy',
bottom: 0,
};
const dynamicTabUnderline = {
left: this.state._leftTabUnderline,
width: this.state._widthTabUnderline,
};
return <View
style={[styles.container, {backgroundColor: this.props.backgroundColor, }, this.props.style, ]}
onLayout={this.onContainerLayout}
>
<ScrollView
ref={(scrollView) => { this._scrollView = scrollView; }}
horizontal={true}
showsHorizontalScrollIndicator={false}
showsVerticalScrollIndicator={false}
directionalLockEnabled={true}
bounces={false}
scrollsToTop={false}
>
<View
style={[styles.tabs, {width: this.state._containerWidth, }, this.props.tabsContainerStyle, ]}
ref={'tabContainer'}
onLayout={this.onTabContainerLayout}
>
{this.props.tabs.map((name, page) => {
const isTabActive = this.props.activeTab === page;
const renderTab = this.props.renderTab || this.renderTab;
return renderTab(name, page, isTabActive, this.props.goToPage, this.measureTab.bind(this, page));
})}
<Animated.View style={[tabUnderlineStyle, dynamicTabUnderline, this.props.underlineStyle, ]} />
</View>
</ScrollView>
</View>;
},
componentWillReceiveProps(nextProps) {
// If the tabs change, force the width of the tabs container to be recalculated
if (JSON.stringify(this.props.tabs) !== JSON.stringify(nextProps.tabs) && this.state._containerWidth) {
this.setState({ _containerWidth: null, });
}
},
onTabContainerLayout(e) {
this._tabContainerMeasurements = e.nativeEvent.layout;
let width = this._tabContainerMeasurements.width;
if (width < WINDOW_WIDTH) {
width = WINDOW_WIDTH;
}
this.setState({ _containerWidth: width, });
this.updateView({value: this.props.scrollValue.__getValue(), });
},
onContainerLayout(e) {
this._containerMeasurements = e.nativeEvent.layout;
this.updateView({value: this.props.scrollValue.__getValue(), });
},
});
module.exports = ScrollableTabBar;
const styles = StyleSheet.create({
tab: {
height: 49,
alignItems: 'center',
justifyContent: 'center',
paddingLeft: 20,
paddingRight: 20,
},
container: {
height: 50,
borderWidth: 1,
borderTopWidth: 0,
borderLeftWidth: 0,
borderRightWidth: 0,
borderColor: '#ccc',
},
tabs: {
flexDirection: 'row',
justifyContent: 'space-around',
},
});