Kotlin 更新来自 activity 的不同布局的 textview 文本

Question

我有一个导航 header 如下我想通过 Kotlin

从 MainActivity.kt 更新 nav_header.xml 中的 TextView

我想从 MainActivity.kt

更新 TextView(id=drawer_user_name) 的文本

main_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">

    <include
        layout="@layout/content_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />


    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recycler_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginTop="45dp"
            android:background="@android:drawable/screen_background_light_transparent"
            tools:listitem="@layout/item_list" />


    </LinearLayout>

    <com.google.android.material.navigation.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header"
        app:menu="@menu/nav_menu" />


</androidx.drawerlayout.widget.DrawerLayout>

nav_header.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="200dp"
    android:background="#4cAF50"
    android:orientation="vertical"
    android:layout_gravity="top"
    android:paddingTop="35dp"
    android:paddingLeft="15dp"
    android:paddingBottom="15dp"
    android:id="@+id/ddd">

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@mipmap/ic_launcher"
        android:id="@+id/imageView"
        android:layout_marginBottom="15dp"/>

    <TextView
        android:id="@+id/drawer_user_name"    //--> i want to update this TextView from MainActivity.kt
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="title"
        android:textColor="#FFFFFF"
        android:textStyle="bold" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="this our navigation drawer"
        android:textColor="#FFFFFF" />

</LinearLayout>

content_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.google.android.material.appbar.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <androidx.appcompat.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/colorPrimary"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:gravity="center_vertical"
                android:orientation="horizontal">

                <TextView
                    style="@style/TextAppearance.AppCompat.Widget.ActionBar.Title"
                    android:id="@+id/home_page_username"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="Chat"
                    android:textColor="#FFFFFF" />
            </LinearLayout>


        </androidx.appcompat.widget.Toolbar>
    </com.google.android.material.appbar.AppBarLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="this is my content"/>
    </LinearLayout>

</LinearLayout>

请帮助我，我真的需要一种方法来解决这个问题
谢谢

Babbab 强迫我们在这里写故事，以便我们 post 提出问题（看来您的 post 主要是代码；请添加更多详细信息）

编辑
我的 MainActivity.kt

package com.example.myapplication

...
import android.view.LayoutInflater
import android.widget.LinearLayout
import kotlinx.android.synthetic.main.activity_main_page.*
import kotlinx.android.synthetic.main.nav_header.view.*

class MainPageActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener,CustomAdapter.OnItemClickListener {

    lateinit var toolbar:androidx.appcompat.widget.Toolbar
    lateinit var drawerLayout: DrawerLayout
    lateinit var navView:NavigationView

    private var data = arrayListOf<UserChanel>()
    private lateinit var myadapter:CustomAdapter
    private val gson = Gson()


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        toolbar =findViewById(R.id.toolbar)
        setSupportActionBar(toolbar)

        drawerLayout = findViewById(R.id.drawer_layout)
        navView = findViewById(R.id.nav_view)

        val toggle = ActionBarDrawerToggle(this,drawerLayout,toolbar,0,0)
        drawerLayout.addDrawerListener(toggle)
        toggle.syncState()
        navView.setNavigationItemSelectedListener(this)

//        val userNameTextView = nav_view.findViewById<TextView>(R.id.drawer_user_name)
//        userNameTextView.text = "SOME TEXT"   // error

        nav_view.drawer_user_name.text = "SOME TEXT"   // Error

       
        val recyclerview = findViewById<RecyclerView>(R.id.recycler_view)



        // for insert line divider to recyclerview items
        recyclerview.addItemDecoration(SimpleDividerItemDecoration(this)) // for insert line divider to recyclerview items

        send_request()

        val adapter = CustomAdapter(this,data,this)
        recyclerview.layoutManager = LinearLayoutManager(this)
        recyclerview.adapter = adapter
        recyclerview.setHasFixedSize(true)
        myadapter = adapter

    }

    override fun onNavigationItemSelected(item: MenuItem): Boolean {
        when(item.itemId){
            R.id.nav_profile->{
                Toast.makeText(this,"profile clicked",Toast.LENGTH_SHORT).show()
            }
            R.id.nav_message->{
                Toast.makeText(this,"message clicked",Toast.LENGTH_SHORT).show()
            }
            R.id.nav_frinds->{
                Toast.makeText(this,"frinds clicked",Toast.LENGTH_SHORT).show()
            }
            R.id.nav_update->{
                Toast.makeText(this,"update clicked",Toast.LENGTH_SHORT).show()
            }
            R.id.nav_logout->{
                Toast.makeText(this,"logout clicked",Toast.LENGTH_SHORT).show()
            }
        }
        drawerLayout.closeDrawer(GravityCompat.START)
        return true
    }
    private fun send_request(){
       ...
    }

    override fun onItemClick(position: Int,adapter: CustomAdapter,v:View) {
        ...
    }

}

Answer 1

您可以通过以下任一方式从 activity 中的 parent 找到目标视图：

nav_view.getHeaderView(0).findViewById<TextView>(R.id.drawer_user_name).text = "SOME TEXT"

或

import kotlinx.android.synthetic.main.nav_header.view.*
...

nav_view.getHeaderView(0).drawer_user_name.text = "SOME TEXT"

根据文档，可以使用 getheaderview(int index) 访问 header 视图。由于您在 NavigationView 中有一个 header 视图，因此可以通过索引 0.

访问它

Kotlin 更新来自 activity 的不同布局的 textview 文本

Kotlin update text of textview on different layout from activity

android

android-layout

android-xml

android-activity

kotlin