Kotlin Navigation开发

时间: 2023-10-04 admin IT培训

Kotlin Navigation开发

Kotlin Navigation开发

前言

其实小编之前一直都是用的Java来开发Android,但是工作需求,开始了Kotlin的编程,接触到了JetPack,发现其中的Navigation特别有意思,今天来给大家分享一下,我们做一个四个页面吧,从APP的 欢迎页面——>新手引导页面——>注册登录页面——>APP主页面 ,我来带大家入门,希望大家不要嫌弃

Navigation的优势

站在Fragment角度:不用把Fragment添加到集合里面去操作了,也不用去操作SupportFragmentManager了

站在Activity角度:可以减少大量的Activity,增加Fragment的使用,毕竟Fragment有更加详细的生命周期,更好的传递信息

站在开发者角度:Navigation的可视化导航图非常优美,导航路径清晰可见,让开发人员更方便的开发

Navigation开发流程

一.注入依赖

    // Kotlin Navigationimplementation("androidx.navigation:navigation-fragment-ktx:2.5.1")implementation("androidx.navigation:navigation-ui-ktx:2.5.1")

二.创建Fragment和XML视图

在app/java/com.example.项目名目录下 先创建一个Fragment文件夹,在文件夹中创建4个Fragment,分别为 WelcomeFragment(欢迎页面),NoviceGuidePageFragment(新手引导页面),RegistrationLandingPageFragment(注册登录页面),MainFragment(APP主页面),具体如下图所示:

在app/res/layout文件夹下创建4个XML,分别为fragment_welcome.xml,fragment_novice_guide_page.xml,fragment_registration_landing_page.xml,fragment_main.xml,具体如下图所示:

WelcomeFragment.kt:

package com.example.siyi2.fragmentimport android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.fragment.app.Fragment
import com.example.siyi2.Rclass WelcomeFragment : Fragment() {override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {val view = inflater.inflate(R.layout.fragment_welcome, container, false)return view}}

fragment_welcome.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android=""xmlns:tools=""android:layout_width="match_parent"android:layout_height="match_parent"><TextViewandroid:id="@+id/to_fragment_novice_guide"android:layout_width="match_parent"android:layout_height="match_parent"android:text="欢迎页面"android:textSize="30dp"android:textColor="@color/black"android:gravity="center"/></androidx.constraintlayout.widget.ConstraintLayout>

NoviceGuidePageFragment.kt:

package com.example.siyi2.fragmentimport android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment
import androidx.navigation.Navigation
import com.example.siyi2.Rclass NoviceGuidePageFragment : Fragment() {override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {val view = inflater.inflate(R.layout.fragment_novice_guide_page, container, false)return view}
}

fragment_novice_guide_page.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android=""android:layout_width="match_parent"android:layout_height="match_parent"><TextViewandroid:id="@+id/to_fragment_registration_landing_page"android:layout_width="match_parent"android:layout_height="match_parent"android:text="新手引导页面"android:textSize="30dp"android:textColor="#F18C8C"android:gravity="center"/></androidx.constraintlayout.widget.ConstraintLayout>

RegistrationLandingPageFragment.kt:

package com.example.siyi2.fragmentimport android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment
import androidx.navigation.Navigation
import com.example.siyi2.Rclass RegistrationLandingPageFragment :Fragment(){override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {val view = inflater.inflate(R.layout.fragment_registration_landing_page,container,false)return view}
}

fragment_registration_landing_page.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android=""android:layout_width="match_parent"android:layout_height="match_parent"><TextViewandroid:id="@+id/to_fragment_main"android:layout_width="match_parent"android:layout_height="match_parent"android:text="登录注册页面"android:textSize="30dp"android:textColor="#DC0404"android:gravity="center"/></androidx.constraintlayout.widget.ConstraintLayout>

MainFragment.kt:

package com.example.siyi2.fragmentimport android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment
import androidx.navigation.Navigation
import com.example.siyi2.Rclass MainFragment :Fragment(){override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {val view = inflater.inflate(R.layout.fragment_main,container,false)return view}
}

fragment_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android=""android:layout_width="match_parent"android:layout_height="match_parent"><TextViewandroid:id="@+id/main_fragment"android:layout_width="match_parent"android:layout_height="match_parent"android:text="APP主页面"android:textSize="30dp"android:textColor="@color/teal_200"android:gravity="center"/></androidx.constraintlayout.widget.ConstraintLayout>

三. 建立Navigation导航图并关联

1.建立导航图

在app/res目录下新建一个文件夹取名navigation,在navigation文件夹下新建nav_graph.xml,如下图所示

 提醒大家一下,我们开发过程中,大家的这个文件夹的名字和XML的名字大家尽量去一些见名知义的名字,方便开发人员和后续维护

nav_graph.xml:

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android=""xmlns:app=""android:id="@+id/nav_graph"app:startDestination="@id/fragment_welcome"><fragmentandroid:id="@+id/fragment_welcome"android:name="com.example.siyi2.fragment.WelcomeFragment"android:label="WelcomeFragment" ><actionandroid:id="@+id/action_fragment_welcome_to_fragment_noviceGuide"app:destination="@id/fragment_noviceGuide"/></fragment><fragmentandroid:id="@+id/fragment_noviceGuide"android:name="com.example.siyi2.fragment.NoviceGuidePageFragment"android:label="NoviceGuideFragment" ><actionandroid:id="@+id/fragment_noviceGuide_to_fragment_registarationLandingpage"app:destination="@+id/fragment_registrationLandingPage" /></fragment><fragmentandroid:id="@+id/fragment_registrationLandingPage"android:name="com.example.siyi2.fragment.RegistrationLandingPageFragment"android:label="RegistrationLandingPageFragment" ><actionandroid:id="@+id/fragment_registrationLandingPage_to_fragment_main"app:destination="@+id/fragment_main" /></fragment><fragmentandroid:id="@+id/fragment_main"android:name="com.example.siyi2.fragment.MainFragment"android:label="MainFragment" ></fragment></navigation>

navigation是根标签,通过startDestinationlai配置默认启动时的第一个页面,小编这里配置的第一个fragment_welcome,我们也可以在代码中动态修改启动时的第一个Fragment,也可以在可视化面板中去修改

fragment标签就代表着这是一个Fragment

name指的是Fragment在项目中的路径

action标签定义了页面跳转的行为,也就是Navigation导航图的每一条线

destination定义跳转的Fragment目标,还可以加入跳转时的动画

Navigation首先要有起始页面,叫startDestination,处于栈底,是启动时的第一个页面,也是返回可见的最后一个页面。多个destination连接起来就构成了一个Navigation导航图,类似于一种栈结构,页面先进后出。destination之间的连接叫做action。

Navigation导航图如下图所示:

 大家可以看到,这样的可视化页面流程导航图非常好看,对吧,这也是Google官方推荐大家使用的,便于开发和维护

2. 为Navigation导航绑定在Activity上

我们的navigation导航图也必须依赖于一个Activity上

MainActivity.kt:

package com.example.siyi2import androidx.appcompat.app.AppCompatActivity
import android.os.Bundleclass MainActivity : AppCompatActivity() {override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity_main)}
}

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android=""xmlns:app=""xmlns:tools=""android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity"><fragmentandroid:id="@+id/nav_host_fragment"app:defaultNavHost="true"app:navGraph="@navigation/nav_graph"android:name="androidx.navigation.fragment.NavHostFragment"android:layout_width="match_parent"android:layout_height="match_parent" /></androidx.constraintlayout.widget.ConstraintLayout>

3. 为Navigation导航页面添加跳转事件

WelcomeFragment.kt:

package com.example.siyi2.fragmentimport android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment
import androidx.navigation.Navigationimport com.example.siyi2.Rclass WelcomeFragment : Fragment() {override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {val view = inflater.inflate(R.layout.fragment_welcome, container, false)view.findViewById<TextView>(R.id.to_fragment_novice_guide).setOnClickListener {Navigation.findNavController(view).navigate(R.id.action_fragment_welcome_to_fragment_noviceGuide)}return view}}

NoviceGuidePageFragment.kt:

package com.example.siyi2.fragmentimport android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment
import androidx.navigation.Navigation
import com.example.siyi2.Rclass NoviceGuidePageFragment : Fragment() {override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {val view = inflater.inflate(R.layout.fragment_novice_guide_page, container, false)view.findViewById<TextView>(R.id.to_fragment_registration_landing_page).setOnClickListener {Navigation.findNavController(view).navigate(R.id.fragment_noviceGuide_to_fragment_registarationLandingpage)}return view}
}

RegistrationLandingPageFragment.kt:

package com.example.siyi2.fragmentimport android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment
import androidx.navigation.Navigation
import com.example.siyi2.Rclass RegistrationLandingPageFragment :Fragment(){override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {val view = inflater.inflate(R.layout.fragment_registration_landing_page,container,false)view.findViewById<TextView>(R.id.to_fragment_main).setOnClickListener {Navigation.findNavController(view).navigate(R.id.fragment_registrationLandingPage_to_fragment_main)}return view}
}

MainFragment.kt:

package com.example.siyi2.fragmentimport android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.fragment.app.Fragment
import androidx.navigation.Navigation
import com.example.siyi2.Rclass MainFragment :Fragment(){override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {val view = inflater.inflate(R.layout.fragment_main,container,false)return view}
}

到此为止,我们就万事俱备,只欠东风了,直接运行,上效果图

四. Navigation效果演示

Navigation开发

不知道大家是否对JetPack中的Navigation感兴趣了呢?请在评论区留言哦!