Android 如何使用kotlin添加按钮片段、ViewPager

我想添加一个按钮（id='Home'），它将我带到我使用这些代码的主要活动，但它没有反应，这是我在GITHUB中的项目示例，请检查它（问题已由@advice dog修复，它已添加到此项目中）

在我拥有的ViewPager布局中：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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/bg2"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:theme="@style/AppFullScreenTheme"
    tools:context=".License">


    <android.support.v4.view.ViewPager
        android:id="@+id/view_pager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="visible"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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/l1_bg"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/fneclis_l1_bg"
    tools:context=".AllButtons">


    <Button
        android:id="@+id/Home"
        android:layout_width="56dp"
        android:layout_height="53dp"
        android:layout_marginBottom="523dp"
        android:layout_marginEnd="312dp"
        android:layout_marginLeft="16dp"
        android:layout_marginRight="312dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:background="@drawable/ic_home_black_24dp"
        android:contentDescription="@string/todo"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

适配器：

package com.medanis.fneclis

import android.app.Activity
import android.content.Context
import android.support.v4.view.PagerAdapter
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup

class CustomPagerAdapter(private val mContext: Context) : PagerAdapter() {

    override fun instantiateItem(collection: ViewGroup, position: Int): Any {
        val modelObject = ModelObject.values()[position]
        val inflater = LayoutInflater.from(mContext)
        val viewGroup = inflater.inflate(modelObject.titleResId, collection, false) as ViewGroup
        collection.addView(viewGroup)
        return viewGroup
    }

    override fun destroyItem(collection: ViewGroup, position: Int, view: Any) {
        collection.removeView(view as View)
    }

    override fun getCount(): Int {
        return ModelObject.values().size
    }

    override fun isViewFromObject(view: View, `object`: Any): Boolean {

        return view === `object`
    }

    override fun getPageTitle(position: Int): CharSequence {
        val customPagerEnum = ModelObject.values()[position]
        return mContext.getString(customPagerEnum.titleResId)
    }

    override fun getItemPosition(`object`: Any): Int {
        return super.getItemPosition(`object`)
    }
}

模型对象：

package com.medanis.fneclis

enum class ModelObject private constructor(val titleResId: Int ) {

    LICENSEONE(R.layout.activity_l1_page),
    PAGEONE(R.layout.activity_l1s1page),
    PAGETWO(R.layout.activity_l1s2page),

    LICENSETWO(R.layout.activity_l2_page),
    PAGETHREE(R.layout.activity_l2_s3page),
    PAGEFOUR(R.layout.activity_l2_s4page),

    LICENSETHREE(R.layout.activity_l3_page),
    PAGEFIVE(R.layout.activity_l3_s5page),
    PAGESIX(R.layout.activity_l3_s6page),

}

---

首先，您没有在查看页面中使用

AllButtons

活动，您只是使用布局并在

CustomPagerAdapter

上对其进行充气，并且由于您没有使用活动，因此未设置主页按钮上的单击侦听器

• 有几件重要的事情需要知道。通过安卓系统。正如您在该页面上所看到的，您只能向视图寻呼机添加片段。因此，您需要将

  所有按钮

  转换为

  片段

  。然后在

  片段的
  方法的
  onViewCreated
  上设置单击侦听器
  
  class AllButtonsFragment: Fragment() { 
       override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
          val root = inflater.inflate(R.layout.activity_l1_page, container, false)
  
          return root
       }
  
       override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
          super.onViewCreated(view, savedInstanceState)
          home.setOnClickListener {
              val intent = Intent(this, MainActivity::class.java)
              startActivity(intent)
          }
       }
  }
  
  

然后在视图寻呼机适配器上创建片段的实例（通过在名为

newInstance（）

的

fragment

上创建一个静态函数来实现这一点，这是一个很好的练习），并根据位置在

instantiateItem

函数上返回适当的片段

    override fun instantiateItem(collection: ViewGroup, position: Int): Any {

         return when (position) {
             0 -> A_FUNCTION.newInstance()
             1 -> B_FUNCTION.newInstance()
             else -> C_FUNCTION.newInstance()
         }
    }

---

我重新编写了您的代码，我将解释一些关于如何改进的提示和建议

首先，始终在

活动

或

片段

的末尾添加

活动

或

片段

，这将有助于使事情更容易理解

class LicenseActivity : AppCompatActivity() {

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

        // You can simply use the id of the View here.
        view_pager.adapter = CustomPagerAdapter(supportFragmentManager)
    }
}

接下来，我将您的

所有按钮

活动

更改为

片段

class AllButtonsFragment: Fragment() { 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        val root = inflater.inflate(R.layout.activity_l1_page, container, false)

        return root
     }

     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        home.setOnClickListener {
            val intent = Intent(this, MainActivity::class.java)
            startActivity(intent)
        }
     }
}

这段代码有点复杂，但它使用了一种非常常见的模式，

newInstance

模式。要创建新的

片段

，您需要创建一个静态方法，该方法将返回一个

片段

，并将您的值传递到

参数

class AllButtonsFragment: Fragment() { 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        val root = inflater.inflate(R.layout.activity_l1_page, container, false)

        return root
     }

     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        home.setOnClickListener {
            val intent = Intent(this, MainActivity::class.java)
            startActivity(intent)
        }
     }
}

class AllButtonsFragment : Fragment() {

    companion object {
        private const val EXTRA_COLOR = "EXTRA_COLOR"
        private const val EXTRA_LAYOUT = "EXTRA_LAYOUT"

        fun newInstance(modelObject: ModelObject): Fragment {
            val fragment = AllButtonsFragment()

            // Creating a Bundle with the various values we want to pass, such as the color and layout.
            val bundle = Bundle()
            bundle.putInt(EXTRA_COLOR, modelObject.titleResId)
            bundle.putInt(EXTRA_LAYOUT, modelObject.layoutResId)
            fragment.arguments = bundle

            return fragment
        }
    }

    // Getting the layout from the arguments to inflate the View.
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        val layout = arguments?.getInt(EXTRA_LAYOUT)
                ?: throw IllegalStateException("arguments does not contain a layout.")
        return inflater.inflate(layout, container, false)
    }

    override fun onViewCreated(view: View?, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        val color = arguments?.getInt(EXTRA_COLOR)
        // TODO: Do whatever with your colour.

        // Using findViewById since this isn't on every layout.
        view?.findViewById<View>(R.id.Home)?.setOnClickListener {
            val intent = Intent(context, MainActivity::class.java)
            startActivity(intent)
        }
    }
}

所以，再解释一下。您创建了一个名为

newInstance

的函数，该函数获取此

片段

应该知道的信息，在本例中，是我们希望它显示的布局

接下来，创建一个

捆绑包

，并将布局放入其中

最后，将

片段

的参数分配给

包

class AllButtonsFragment: Fragment() { 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        val root = inflater.inflate(R.layout.activity_l1_page, container, false)

        return root
     }

     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        home.setOnClickListener {
            val intent = Intent(this, MainActivity::class.java)
            startActivity(intent)
        }
     }
}

这是创建

片段的最安全的方法

class AllButtonsFragment: Fragment() { 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        val root = inflater.inflate(R.layout.activity_l1_page, container, false)

        return root
     }

     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        home.setOnClickListener {
            val intent = Intent(this, MainActivity::class.java)
            startActivity(intent)
        }
     }
}

class AllButtonsFragment : Fragment() {

    companion object {
        private const val EXTRA_COLOR = "EXTRA_COLOR"
        private const val EXTRA_LAYOUT = "EXTRA_LAYOUT"

        fun newInstance(modelObject: ModelObject): Fragment {
            val fragment = AllButtonsFragment()

            // Creating a Bundle with the various values we want to pass, such as the color and layout.
            val bundle = Bundle()
            bundle.putInt(EXTRA_COLOR, modelObject.titleResId)
            bundle.putInt(EXTRA_LAYOUT, modelObject.layoutResId)
            fragment.arguments = bundle

            return fragment
        }
    }

    // Getting the layout from the arguments to inflate the View.
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        val layout = arguments?.getInt(EXTRA_LAYOUT)
                ?: throw IllegalStateException("arguments does not contain a layout.")
        return inflater.inflate(layout, container, false)
    }

    override fun onViewCreated(view: View?, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        val color = arguments?.getInt(EXTRA_COLOR)
        // TODO: Do whatever with your colour.

        // Using findViewById since this isn't on every layout.
        view?.findViewById<View>(R.id.Home)?.setOnClickListener {
            val intent = Intent(context, MainActivity::class.java)
            startActivity(intent)
        }
    }
}

您如何使用
所有按钮
类？似乎您只是在
适配器中构建
视图
，但是不要使用
AllButtons
类。我是初学者，请告诉我该怎么做？给我几分钟时间。慢慢来，请不要忘记我这些答案对你有帮助吗？它给了我一个关于a_函数/b_函数和C_函数的错误。我在github中添加了一个项目示例，请检查一下，不要给我一个关于allbuttonf片段的错误：return setContentView（layout）and in Intent（）我在github中添加了一个项目示例，请检查一下，我犯了一些错误。我把它们修好了，我甚至还为你的回购提出了一个请求。现在一切都应该正常了。我已经更新了我的答案，以反映这些代码更改。谢谢。我明天会检查它，并告诉您发生了什么。^再次感谢