# Other

### **元件的位置和長寬（元件大小）**

```
<View style={styles.row}
    onLayout={(event) => {
        var {x, y, width, height} = event.nativeEvent.layout;
    }
}/>
```

###

### **字體大小不被系統字體大小影響（just for iOS）**

```
Text.defaultProps.allowFontScaling = false;
```

### **獲取螢幕寬高（Dimensions）**

[RN官網](https://facebook.github.io/react-native/docs/dimensions.html)

```
import { Dimensions, } from 'react-native'
    export var windowH = Dimensions.get('window').height;
    export var windowW = Dimensions.get('window').width;
or
    var {height, width} = Dimensions.get('window')
```

### **PixelRatio（像素比）（螢幕密度！？）**

參考 [RN官網](https://facebook.github.io/react-native/docs/pixelratio.html)

**平台（Android|iOS）（Platform Specific Code）**

(Android version) (iOS version) [RN官網](https://facebook.github.io/react-native/docs/platform-specific-code.html)

### &#x20;**監聽鍵盤(Show、Hide）**

參考 [Avoiding the Keyboard in React Native](https://shift.infinite.red/avoiding-the-keyboard-in-react-native-56d05b9a1e81)

```
import { Keyboard } from 'react-native'

...

constructor() {
    super();
    this.state = {
        //change money's input position
        isKeyboardShow: true,
        //for ios's softkeyboard
        keyboardHeight: 0,
    }
}

componentWillMount() {
    this.keyboardDidShowListener = Keyboard.addListener('keyboardDidShow', (e) => this.keyboardDidShow(e));
    this.keyboardDidHideListener = Keyboard.addListener('keyboardDidHide', () => this.keyboardDidHide());
}

componentWillUnmount() {
    this.keyboardDidShowListener.remove();
    this.keyboardDidHideListener.remove();
}

keyboardDidShow(e) {
    this.setState({
        isKeyboardShow: true,
        keyboardHeight: e.endCoordinates.height, //測量鍵盤高度
    });
}

keyboardDidHide() {
    this.setState({
        isKeyboardShow: false,
        keyboardHeight: 0,
    });
}

...
```