我希望这是一个非常简单的答案。我正在用android（一个运动追踪器）开发我的第一个真实应用程序，我希望它能为大多数应用程序提供一个导航抽屉布局。我有一堆页面，我想让抽屉导航到。我已经弄清楚了如何更改activity_main_drawer.xml菜单文件中菜单项的名称，但是当用户点击它们时，我不知道如何附加导航。我的代码是模板中的默认代码：
MainActivity.kt
package com.example.grahamfitnesstracker
import android.os.Bundle
import android.support.design.widget.FloatingActionButton
import android.support.design.widget.Snackbar
import android.support.v4.view.GravityCompat
import android.support.v7.app.ActionBarDrawerToggle
import android.view.MenuItem
import android.support.v4.widget.DrawerLayout
import android.support.design.widget.NavigationView
import android.support.v7.app.AppCompatActivity
import android.support.v7.widget.Toolbar
import android.view.Menu
class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val toolbar: Toolbar = findViewById(R.id.toolbar)
setSupportActionBar(toolbar)
val fab: FloatingActionButton = findViewById(R.id.fab)
fab.setOnClickListener { view ->
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show()
}
val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
val navView: NavigationView = findViewById(R.id.nav_view)
val toggle = ActionBarDrawerToggle(
this, drawerLayout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close
)
drawerLayout.addDrawerListener(toggle)
toggle.syncState()
navView.setNavigationItemSelectedListener(this)
}
override fun onBackPressed() {
val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
drawerLayout.closeDrawer(GravityCompat.START)
} else {
super.onBackPressed()
}
}
override fun onCreateOptionsMenu(menu: Menu): Boolean {
// Inflate the menu; this adds items to the action bar if it is present.
menuInflater.inflate(R.menu.main, menu)
return true
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
return when (item.itemId) {
R.id.action_settings -> true
else -> super.onOptionsItemSelected(item)
}
}
override fun onNavigationItemSelected(item: MenuItem): Boolean {
// Handle navigation view item clicks here.
when (item.itemId) {
R.id.nav_current_workout -> {
// Handle the camera action
}
R.id.nav_log -> {
}
R.id.nav_exercises -> {
}
R.id.nav_workouts -> {
}
R.id.nav_stats -> {
}
R.id.nav_settings -> {
}
}
val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
drawerLayout.closeDrawer(GravityCompat.START)
return true
}
}
和导航抽屉菜单activity_main_drawer.xml
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
tools:showIn="navigation_view">
<group android:checkableBehavior="single">
<item
android:id="@+id/nav_current_workout"
android:icon="@drawable/ic_menu_play_filled"
android:title="@string/menu_current_workout"/>
<item
android:id="@+id/nav_log"
android:icon="@drawable/ic_menu_log"
android:title="@string/menu_log"/>
<item
android:id="@+id/nav_exercises"
android:icon="@drawable/ic_menu_weight"
android:title="@string/menu_exercises"/>
<item
android:id="@+id/nav_workouts"
android:icon="@drawable/ic_menu_person"
android:title="@string/menu_workouts"/>
<item
android:id="@+id/nav_stats"
android:icon="@drawable/ic_menu_chart"
android:title="@string/menu_stats"/>
</group>
<item android:title="">
<menu>
<item
android:id="@+id/nav_settings"
android:icon="@drawable/ic_menu_settings"
android:title="@string/menu_settings"/>
</menu>
</item>
</menu
最后，我假定的content_main.xml是我需要放置片段的位置（我仍然不完全了解...）。从一个指南中，我将其更改为包括一个FrameLayout：
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:showIn="@layout/app_bar_main"
tools:context=".MainActivity">
<!-- Note : This is the container Frame Layout for all the fragments-->
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/mainFrame">
</FrameLayout>
</android.support.constraint.ConstraintLayout>
我真的只是不知道要在MainActivity.kt的onNavigationItemSelected项中添加什么以便处理导航。我了解到我需要用放在页面用户界面中的某些片段替换content_main.xml中的内容，但是我不知道该怎么做。谁能帮我吗？我看了很多示例，但是它们通常实现自己的自定义导航栏，或者使用的Java使我感到困惑。
答案 0 :(得分：0)
您是否已将big_array包含在NavigationView中，并将此activity_main添加到该视图中，如下所示：
nav_header_man
activity_main并且由于您要求在MainActivity.kt中的onNavigationItemSelected项中添加什么内容，
<?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/app_bar_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<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_main"
app:menu="@menu/activity_main_drawer" >
</com.google.android.material.navigation.NavigationView>
</androidx.drawerlayout.widget.DrawerLayout>
MainActivity.kt希望这会有所帮助。
答案 1 :(得分：0)
导航抽屉的Xml布局：
<include
layout="@layout/dashboard_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<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"
app:headerLayout="@layout/nav_header_main"
app:menu="@menu/drawer_menu" />
在Kotlin文件中的实现：
class MainActivity :
AppCompatActivity(),NavigationView.OnNavigationItemSelectedListener {
private lateinit var drawer: DrawerLayout
private lateinit var navigationView: NavigationView
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val toolbar: Toolbar = findViewById(R.id.toolbar_main)
setSupportActionBar(toolbar)
drawer = findViewById(R.id.drawer_layout)
toggle = ActionBarDrawerToggle(
dis,
drawer,
toolbar,
R.string.navigation_drawer_open,
R.string.navigation_drawer_close
)
drawer.addDrawerListener(toggle)
toggle.setDrawerIndicatorEnabled(true)
toggle.syncState()
navigationView = findViewById(R.id.nav_view)
navigationView.setNavigationItemSelectedListener(dis)
}
override fun onNavigationItemSelected(item: MenuItem): Boolean {
when (item.itemId) {
R.id.login_signup -> {
startActivity(Intent(dis, LoginActivity::class.java).putExtra("go_to","0"))
}
}
drawer.closeDrawers()
return true
}
}