vue子组件调用父组件的方法

<template>
  <div>
    <child></child>
  </div>
</template>
<script>
  import child from './child';
  export default {
    components: {
      child
    },
    methods: {
      fatherMethod(str) {
        console.log(str);
      }
    }
  };
</script>

<template>
  <div>
    <button @click="childMethod">点击</button>
  </div>
</template>
<script>
  export default {
    methods: {
      childMethod() {
        this.$parent.fatherMethod('hello');
      }
    }
  };
</script>

<template>
  <div>
    <child :fatherMethod="fatherMethodOther"></child>
  </div>
</template>
<script>
  import child from './child';
  export default {
    components: {
      child
    },
    methods: {
      fatherMethodOther(str) {
        console.log(str);
      }
    }
  };
</script>

<template>
  <div>
    <button @click="childMethod">点击</button>
  </div>
</template>
<script>
  export default {
    props: {
      fatherMethod: {
        type: Function,
        default: null
      }
    },
    methods: {
      childMethod() {
        if (this.fatherMethod) {
          this.fatherMethod('hello');
        }
      }
    }
  };
</script>

<template>
  <div>
    <child @fatherMethod="fatherMethodOther"></child>
  </div>
</template>
<script>
  import child from './child';
  export default {
    components: {
      child
    },
    methods: {
      fatherMethodOther(str) {
        console.log(str);
      }
    }
  };
</script>

<template>
  <div>
    <button @click="childMethod">点击</button>
  </div>
</template>
<script>
  export default {
    methods: {
      childMethod() {
        this.$emit('fatherMethod', 'hello');
      }
    }
  };
</script>