方案一：通过ref直接调用子组件的方法；

//父组件中

<template>
    <div>
        <div @click="handleClick">点击调用子组件方法</div>
        <Child ref="child"/>
    </div>
</template>    

<script>
import Child from './child';

export default {
    methods: {
        handleClick() {
              this.$refs.child.sing();
        },
    },
    components: {
      Child
    }
}
</script>


//子组件中

<template>
  <div>我是子组件</div>
</template>
<script>
export default {
  methods: {
    sing() {
      console.log('我是子组件的方法');
    },
  },
};
</script>

方案二：通过组件的$emit、$on方法；

//父组件中

<template>
    <div>
        <div @click="handleClick">点击调用子组件方法</div>
        <Child ref="child"/>
    </div>
</template>    

<script>
import Child from './child';

export default {
	components: {
      Child
    }
    methods: {
        handleClick() {
               this.$refs.child.$emit("childmethod")    //子组件$on中的名字
        },
    },
}
</script>

//子组件中

<template>
    <div>我是子组件</div>
</template>
<script>
export default {
    mounted() {
        this.$nextTick(function() {
            this.$on('childmethods', function() {
                console.log('我是子组件方法');
            });
        });
     },
};
</script>

直接在子组件中通过this.$parent.event来调用父组件的方法

//父组件
<template>
  <div>
    <child></child>
  </div>
</template>
<script>
  import child from './components/dam/child';
  export default {
    components: {
      child
    },
    methods: {
      fatherMethod() {
        console.log('测试');
      }
    }
  };
</script>
//子组件
<template>
  <div>
    <div @click="childMethod()">点击</div>
  </div>
</template>
<script>
  export default {
    methods: {
      childMethod() {
        this.$parent.fatherMethod();
      }
    }
  };
</script>

在子组件里用$emit向父组件触发一个事件，父组件监听这个事件就行了。

//父组件
<template>
  <div>
    <child @fatherMethod="fatherMethod"></child>
  </div>
</template>
<script>
  import child from '~/components/dam/child';
  export default {
    components: {
      child
    },
    methods: {
      fatherMethod() {
        console.log('测试');
      }
    }
  };
</script>
//子组件
<template>
  <div>
    <div @click="childMethod()">点击</div>
  </div>
</template>
<script>
  export default {
    methods: {
      childMethod() {
        this.$emit('fatherMethod');
      }
    }
  };
</script>

父组件把方法传入子组件中，在子组件里直接调用这个方法

//父组件
<template>
  <div>
    <child :fatherMethod="fatherMethod"></child>
  </div>
</template>
<script>
  import child from '~/components/dam/child';
  export default {
    components: {
      child
    },
    methods: {
      fatherMethod() {
        console.log('测试');
      }
    }
  };
</script>
//子组件
<template>
  <div>
    <div @click="childMethod()">点击</div>
  </div>
</template>
<script>
  export default {
    props: {
      fatherMethod: {
        type: Function,
        default: null
      }
    },
    methods: {
      childMethod() {
        if (this.fatherMethod) {
          this.fatherMethod();
        }
      }
    }
  };
</script>
//子组件更简单的方法
<template>
  <div>
    <div @click="fatherMethod()">点击</div>
  </div>
</template>
<script>
  export default {
    props: {
      fatherMethod: {
        type: Function,
        default: null
      }
    },
    methods: {
      
    }
  };
</script>