本文为转载文章，只因原作者写的太好了，读完瞬间理解，原网址：http://blog.csdn.net/tomasyb/article/details/71680342

生命周期图

20170511182906291.png
20170511173234404.png

进入页面打印日志

加载阶段

20170511173443333.png

点击我日志

20170511173547178.png

点击让他死亡

--------componentWillUnmount组件移除前调用---------------

让他重生就回到加载阶段

20170511173443333.png

项目源码

export default class LifeComponent extends Component {
    //构造方法
    constructor(props) {
        super(props)
        //定义state()
        this.state = {
            count: 0,
        }
        console.log('--------constructor构造方法---------------')
    }

    //组件装载前
    componentWillMount() {
        console.log('--------componentWillMount组件装载前---------------')
    }

    //组件装载后
    componentDidMount() {
        console.log('--------componentDidMount组件装载后---------------')
    }

    //组件跟新调用
    componentWillReceiveProps(nextProps) {
        console.log('--------componentWillReceiveProps组件跟新调用---------------')
    }

    //组件是否跟新
    shouldComponentUpdate(nextProps, nextState) {
        console.log('--------shouldComponentUpdate组件是否跟新---------------')
        //默认返回true让他跟新
        return true;
    }

    //组件跟新前调用
    componentWillUpdate(nextProps, nextState) {
        console.log('--------componentWillUpdate组件跟新前调用---------------')
    }

    //组件跟新后调用
    componentDidUpdate(prevProps, prevState) {
        console.log('--------componentDidUpdate组件跟新后调用---------------')
    }

    //组件移除前调用
    componentWillUnmount() {
        console.log('--------componentWillUnmount组件移除前调用---------------')
    }

    //渲染
    render() {
        console.log('--------render渲染---------------')
        return (
            <View>
                <Text
                    style={{fontSize: 20, backgroundColor: 'red'}}
                    onPress={() => {
                        this.setState({
                            count: this.state.count + 1,
                        })
                    }}

                >点击我</Text>

                <Text style={{fontSize: 20, backgroundColor: 'blue'}}

                >被点了{this.state.count}次</Text>
            </View>
        );
    }
}

setup使用组件

import LifeComponent from '../common/LifeComponent'
export default class setup extends Component {
    //模拟卸载
    constructor(props) {
        super(props);
        this.state = ({
            remove: false,
        })
    }
    render() {
        var view = this.state.remove?null:<LifeComponent/>;
        var text = this.state.remove? '让他重生':'让他死亡';
        return (
            <View style={styles.container}>
                <Text style={{fontSize:20}}
                      onPress={()=>{
                          this.setState({
                              remove:!this.state.remove,
                          })
                      }}
                >{text}</Text>
                {view}
            </View>
        );
    }
}