//返回事件的監聽，也就是app:navigationIcon屬性設置的圖片的監聽
idToolBar.setNavigationOnClickListener {
    Toast.makeText(this, "點擊了返回", Toast.LENGTH_SHORT).show()
}
//右側點擊的監聽
idToolBar.setOnMenuItemClickListener {
    Toast.makeText(this, it.title, Toast.LENGTH_SHORT).show()
    true
}

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item
        android:id="@+id/idTooBarMenuOne"
        android:icon="@mipmap/icon_xin_no"
        android:orderInCategory="1"
        android:title="搜索"
        app:showAsAction="ifRoom|collapseActionView"
        app:actionViewClass="androidx.appcompat.widget.SearchView " />
</menu>

<androidx.appcompat.widget.Toolbar
    android:id="@+id/idToolBar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#0000ff"
    app:collapseIcon="@mipmap/icon_xin_yes"
    app:menu="@menu/menu"
    app:titleTextColor="#ff0000" />

//注意import引入的SearchView 要和 menu的item中app:actionViewClass屬性一致
val searchView: SearchView = idToolBar.menu.findItem(R.id.idTooBarMenuOne).actionView as SearchView
//設置搜索提示語
searchView.queryHint = "搜索"
searchView.setOnSearchClickListener {
    //當點擊搜索編輯框的時候回調，剛進入的時候默認是點擊搜索編輯框的
    Toast.makeText(this@ActivityToolBar, "點擊了搜索框", Toast.LENGTH_SHORT).show()
}
searchView.setOnQueryTextListener(object : SearchView.OnQueryTextListener {
    override fun onQueryTextSubmit(s: String?): Boolean {
        //點擊手機軟鍵盤搜索按鈕的時候回調
        Toast.makeText(this@ActivityToolBar, "點擊了搜索", Toast.LENGTH_SHORT).show()
        return false
    }
    override fun onQueryTextChange(s: String?): Boolean {
        //當搜索框中文本發生改變的時候執行
        return false
    }
})
searchView.setOnQueryTextFocusChangeListener { v, hasFocus ->
    //當得到焦點和失去焦點的時候執行
    if (hasFocus) {
        Toast.makeText(this@ActivityToolBar, "獲取了焦點", Toast.LENGTH_SHORT).show()
    } else {
        Toast.makeText(this@ActivityToolBar, "失去了焦點", Toast.LENGTH_SHORT).show()
    }
}
idToolBar.menu.findItem(R.id.idTooBarMenuOne).setOnActionExpandListener(object : MenuItem.OnActionExpandListener {
    override fun onMenuItemActionExpand(item: MenuItem?): Boolean {
        //展開時執行
        Toast.makeText(this@ActivityToolBar, "進行了展開", Toast.LENGTH_SHORT).show()
        return true
    }
    override fun onMenuItemActionCollapse(item: MenuItem?): Boolean {
        //收起時回調
        Toast.makeText(this@ActivityToolBar, "進行了收縮", Toast.LENGTH_SHORT).show()
        return true
    }
})

idToolBar.overflowIcon=ContextCompat.getDrawable(this,R.mipmap.dragon_eight)