button.setOnClickListener正在使我的應用程式崩潰。科特林1.3.72-有解無憂

所以首先我知道不再支持 kotlin android 擴展。我稍后會改變它。首先，我想確保我的應用程式可以正常作業并具有它需要的東西，然后我會收斂。我對 android studio 有點陌生，所以我有可能錯過了一些簡單的東西。我做了匯入按鈕和吐司。

如果我洗掉按鈕 onclick 偵聽器，我的應用程式作業正常，所以我認為它一定是罪魁禍首。

主要活動

package com.dispatch.tripsheet

import android.os.Bundle
import android.view.View
import android.widget.*
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import kotlinx.android.synthetic.main.activity_main.*
import kotlinx.android.synthetic.main.table_list_item.*

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


        recyclerViewMovieList.layoutManager = LinearLayoutManager(this)

        recyclerViewMovieList.adapter = TableViewAdapter(movieList)


        // get reference to button
      //  val button1 = findViewById(R.id.button1) as Button

//        button1.setOnClickListener {
//
//            Toast.makeText(this@MainActivity, "You clicked me.", Toast.LENGTH_SHORT).show()
//          tvdone.setBackgroundResource(R.color.green)
//
//        }

//        // get reference to button
//     //   val button2 = findViewById(R.id.button2) as Button
//        // set on-click listener
//        button2.setOnClickListener {
//            // your code to perform when the user clicks on the button
//            Toast.makeText(this@MainActivity, "You clicked me.", Toast.LENGTH_SHORT).show()
//          tvdone.setBackgroundResource(R.color.orange)
//
//        }


        val button1 = findViewById(R.id.button1) as Button
        button1.setOnClickListener {
            Toast.makeText(this@MainActivity, "You clicked me.", Toast.LENGTH_SHORT).show()
            tvdone.setBackgroundResource(R.color.green)
        }
//        button2.setOnClickListener {
//            Toast.makeText(this@MainActivity, "You clicked me.", Toast.LENGTH_SHORT).show()
//            tvdone.setBackgroundResource(R.color.orange)
//        }

//            colour_orange(View view) {
//                // set the color to relative layout
//                relativeLayout.setBackgroundResource(R.color.cool)
//            }
//        });

//        // onClick function for button 2
//        button2.setOnClickListener(new View.OnClickListener() {
//            @Override
//            public void onClick(View view) {
//                // set the color to relative layout
//                relativeLayout.setBackgroundResource(R.color.warm)
//            }


        val list : MutableList<String> = ArrayList()
        list.add("Deon")
        list.add("Leon")
        list.add("David")
        list.add("Dick")
        list.add("Jim")
        list.add("Harry")


        val adapter = ArrayAdapter( this, androidx.appcompat.R.layout.support_simple_spinner_dropdown_item, list)
        val spinner: Spinner = findViewById(R.id.spnDriver)

        spinner.adapter = adapter

        spinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener{
            override fun onItemSelected(p0: AdapterView<*>?, p1: View?, p2: Int, p3: Long) {
                val item :String = list[p2]

                Toast.makeText(this@MainActivity, "Driver $item selected", Toast.LENGTH_SHORT).show()
            }

            override fun onNothingSelected(p0: AdapterView<*>?) {
                //empty
            }

            //insert code that activates data pull of tripsheet for driver=


        }

        limitDropDownHeight(spinner)


    }
    fun limitDropDownHeight(spinner: Spinner){



        val popup = Spinner::class.java.getDeclaredField( "mPopup")
        popup.isAccessible = true

        val popupWindow = popup.get(spinner)as ListPopupWindow

        popupWindow.height = (200 * resources.displayMetrics.density).toInt()



    }

     val movieList = ArrayList<MovieModel>().apply {


//         var x: Int = 10
//
//         for (i in 1..x) {
//             println(i)
//
//
//         }

//         var totweight: Int = 40
//         tvTotalweight.setText("Total Weight: "  totweight  "kg")

        add(MovieModel(190617, 182832, "Jcorp", "378 Begonia 6th street",100))
        add(MovieModel(190617, 182833, "Honda", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Panado", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Gheiters", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "John", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(9190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(190617, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(10, 182832, "Everflu", "365 hellington rogmastreet",100))
        add(MovieModel(10, 182832, "2010", "260",100))
        add(MovieModel(10, 182832, "2010", "260",100))
        add(MovieModel(10, 182832, "2010", "260",100))
        add(MovieModel(10, 182832, "2010", "260",100))
        add(MovieModel(10, 182832, "2010", "260",100))
        add(MovieModel(10, 182832, "2010", "260",100))
        add(MovieModel(10, 182832, "2010", "260",100))


     //need to change from hardcoded text to input
         
     }

    fun weightsum(args: Array<String>) {
        var totweight: Int = 40
        var sum: Int = 0
        //  var input: String

//        for (Int sum : movieList)
//        {
//            System.out.println(sum);
//        }


        tvTotalweight.setText("Total Weight: "  totweight  "kg")



    }


}

完整的 XML：

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

    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <TextView
        android:id="@ id/txtWOrder"
        android:layout_width="160dp"
        android:layout_height="match_parent"
        android:layout_gravity="top"

        android:background="@drawable/table_content_cell_bg"
        android:text="WOrder"
        android:textSize="18sp" />

    <TextView
        android:id="@ id/txtDElNote"
        android:layout_width="190dp"

        android:layout_height="match_parent"
        android:layout_gravity="top"
        android:background="@drawable/table_content_cell_bg"
        android:text="DElNote"
        android:textSize="18sp" />

    <TextView
        android:id="@ id/txtCompany"
        android:layout_width="190dp"

        android:layout_height="match_parent"
        android:layout_gravity="top"
        android:background="@drawable/table_content_cell_bg"
        android:text="Company"
        android:textSize="18sp" />

    <TextView
        android:id="@ id/txtWeight"
        android:layout_width="190dp"
        android:layout_height="match_parent"
        android:layout_gravity="top"
        android:background="@drawable/table_content_cell_bg"
        android:text="Weight"
        android:textSize="18sp" />

<!--    <TextView-->
<!--        android:id="@ id/txtAddress"-->
<!--        android:layout_width="550dp"-->
<!--        android:layout_height="match_parent"-->
<!--        android:layout_gravity="top"-->
<!--        android:background="@drawable/table_content_cell_bg"-->
<!--        android:text="Address"-->
<!--        android:textSize="18sp" />-->


    <!--        android:onClick="ButtonName.setBackgroundDrawable(getResources().getDrawable(R.drawable.ImageName))"-->

    <Button
        android:id="@ id/button1"
        android:layout_width="250dp"
        android:layout_height="match_parent"
        android:layout_gravity="top"
        android:background="@drawable/table_content_cell_bg"


        android:text="@string/button1"
        android:textSize="18sp" />




    <Button
        android:id="@ id/button2"
        android:layout_width="250dp"
        android:layout_height="match_parent"
        android:layout_gravity="top"
        android:background="@drawable/table_content_cell_bg"

        android:text="@string/button2"
        android:textSize="18sp" />

    <TextView
        android:id="@ id/tvdone"
        android:layout_width="50dp"
        android:layout_height="match_parent"
        android:background="@drawable/table_content_cell_bg"
        android:text="" />


</LinearLayout>

這個是為了填補我的recyclerview。接下來是我的activtymain。：

<?xml version="1.0" encoding="utf-8"?>
<TableLayout 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:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:gravity="center"
    tools:context=".MainActivity"
    android:stretchColumns="*">

    <TableRow
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_margin="1dp"
        android:layout_weight="1"
        android:background="#FFFFFF">

        <TextView
            android:id="@ id/tvHeader"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:text="Vulcan Steel Trip Sheet: ID NUM TRIPSHEET"
            android:textAppearance="@style/TextAppearance.AppCompat.Medium"
            android:textColor="#000000"
            android:textSize="24sp"
            android:textStyle="bold" />

        <androidx.appcompat.widget.AppCompatSpinner
            android:id="@ id/spnDriver"
            android:layout_width="0dp"
            android:layout_height="48dp"
            android:layout_margin="10dp"
            android:layout_weight="1"
            android:background="@drawable/spinner_bg"
            android:contentDescription="@string/driver"
            android:spinnerMode="dropdown" />


    </TableRow>

<!--    <TableRow-->
<!--        android:layout_width="0dp"-->
<!--        android:layout_height="wrap_content"-->
<!--        android:layout_margin="1dp"-->
<!--        android:layout_weight="1"-->
<!--        android:id="@ id/headerrow"-->

<!--        android:background="#ffffff">-->

<!--        <TextView-->
<!--        android:layout_width="0dp"-->
<!--        android:layout_weight="1"-->
<!--        android:layout_height="wrap_content"-->
<!--        android:layout_column="0"-->
<!--        android:layout_margin="1dp"-->
<!--        android:background="#FFFFFF"-->
<!--        android:gravity="center"-->
<!--        android:text=" W Order "-->
<!--        android:textAppearance="?android:attr/textAppearanceLarge"-->
<!--        android:textStyle="bold" />-->

<!--    <TextView-->
<!--        android:layout_width="0dp"-->
<!--        android:layout_weight="1"-->
<!--        android:layout_height="wrap_content"-->
<!--        android:layout_column="1"-->
<!--        android:layout_margin="1dp"-->
<!--        android:background="#FFFFFF"-->
<!--        android:gravity="center"-->
<!--        android:text="Del Note "-->
<!--        android:textAppearance="?android:attr/textAppearanceLarge"-->
<!--        android:textStyle="bold" />-->

<!--    <TextView-->
<!--        android:layout_width="0dp"-->
<!--        android:layout_weight="1"-->
<!--        android:layout_height="wrap_content"-->
<!--        android:layout_column="2"-->
<!--        android:layout_margin="1dp"-->
<!--        android:background="#FFFFFF"-->
<!--        android:gravity="center"-->
<!--        android:text="Company"-->
<!--        android:textAppearance="?android:attr/textAppearanceLarge"-->
<!--        android:textStyle="bold" />-->

<!--    <TextView-->
<!--        android:layout_width="0dp"-->
<!--        android:layout_weight="4"-->
<!--        android:layout_height="wrap_content"-->
<!--        android:layout_column="2"-->
<!--        android:layout_margin="1dp"-->
<!--        android:background="#FFFFFF"-->
<!--        android:gravity="center"-->
<!--        android:text="Address"-->
<!--        android:textAppearance="?android:attr/textAppearanceLarge"-->
<!--        android:textStyle="bold" />-->


<!--    <TextView-->
<!--        android:layout_width="0dp"-->
<!--        android:layout_weight="1"-->
<!--        android:layout_height="wrap_content"-->
<!--        android:layout_column="2"-->
<!--        android:layout_margin="1dp"-->
<!--        android:background="#FFFFFF"-->
<!--        android:gravity="center"-->
<!--        android:text="Weight"-->
<!--        android:textAppearance="?android:attr/textAppearanceLarge"-->
<!--        android:textStyle="bold" />-->

<!--    </TableRow>-->

    <TableRow
        android:layout_width="match_parent"
        android:layout_height="570dp"
        android:layout_margin="1dp"

        android:background="#ffffff"
        >

        <HorizontalScrollView
            android:layout_width="wrap_content"
            android:layout_height="570dp"
            android:layout_margin="0dp"



            >


            <androidx.recyclerview.widget.RecyclerView
                android:id="@ id/recyclerViewMovieList"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"

                android:nestedScrollingEnabled="false"
                tools:listitem="@layout/table_list_item" />

        </HorizontalScrollView>


    </TableRow>








    <TableRow
        android:id="@ id/footerow"
        android:background="#ffffff"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="match_parent">

        <TextView
            android:id="@ id/tvTotaldelv"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="6"
            android:text="Total: x Delivery Notes"
            android:textColor="#000000"
            android:textSize="15sp"
            android:textStyle="bold" />

        <TextView
            android:id="@ id/tvTotalweight"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Total weight: # xkg"
            android:textColor="#000000"
            android:textSize="15sp" />
    </TableRow>


</TableLayout>

我已經去掉了吐司和顏色的變化，看看是否可能是它。但它還是崩潰了。所以不確定我錯過了什么。

Error log: 
2022-03-10 13:42:37.876 20228-20228/com.dispatch.tripsheet E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.dispatch.tripsheet, PID: 20228
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.dispatch.tripsheet/com.dispatch.tripsheet.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3835)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4011)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2325)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:246)
        at android.app.ActivityThread.main(ActivityThread.java:8633)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
        at com.dispatch.tripsheet.MainActivity.onCreate(MainActivity.kt:25)
        at android.app.Activity.performCreate(Activity.java:8207)
        at android.app.Activity.performCreate(Activity.java:8191)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3808)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4011) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2325) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:246) 
        at android.app.ActivityThread.main(ActivityThread.java:8633) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)

我不確定這到底是什么意思。只是告訴我按鈕發生了什么。但我不知道更多。在崩潰前顯示應用程式的影像。因此，在我嘗試添加 clicklistener 之前，一切正常。

uj5u.com熱心網友回復：

@helpVulcan 這是配接器代碼片段，您可以根據需要使用和自定義，

class MyAdapter(val list: ArrayList<String>) : RecyclerView.Adapter<MyAdapter.MyViewHolder>() {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
        return MyViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.table_list_item, parent, false))
    }

    override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
        holder.apply {
            button1.setOnClickListener {
                Log.e("Clicked", "button1")
                //  Toast.makeText(this@MainActivity, "You clicked me.", Toast.LENGTH_SHORT).show()
            }
        }
    }

    override fun getItemCount(): Int {
        return list.size
    }

    class MyViewHolder(val view: View) : RecyclerView.ViewHolder(view) {
        var button1 = view.findViewById<Button>(R.id.button1)
    }

}

uj5u.com熱心網友回復：

看起來您的按鈕未找到。您如何訪問它以及在哪里訪問它？請記住，該按鈕首先需要存在，以便您可以獲取對它的參考。您可以使用 findViewById 方法或視圖系結。

轉載請註明出處，本文鏈接：https://www.uj5u.com/qianduan/440838.html

標籤：安卓科特林 button onclick

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