Android秒表应用程序崩溃

Question

所以我有这个秒表但是当我打开它的活动时，这就是我得到的：

FATAL EXCEPTION: main
Process: com.reecreate.woderator2, PID: 5869
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.reecreate.woderator2/com.reecreate.woderator2.Controller.StopwatchActivity}: kotlin.UninitializedPropertyAccessException: lateinit property textView has not been initialized
                                                                            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2665)
                                                                            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)
                                                                            at android.app.ActivityThread.-wrap12(ActivityThread.java)
                                                                            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)
                                                                            at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                            at android.os.Looper.loop(Looper.java:154)
                                                                            at android.app.ActivityThread.main(ActivityThread.java:6119)
                                                                            at java.lang.reflect.Method.invoke(Native Method)
                                                                            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                                                                            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
                                                                         Caused by: kotlin.UninitializedPropertyAccessException: lateinit property textView has not been initialized
                                                                            at com.reecreate.woderator2.Controller.StopwatchActivity.onCreate(StopwatchActivity.kt:52)
                                                                            at android.app.Activity.performCreate(Activity.java:6679)
                                                                            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
                                                                            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2618)
                                                                            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726) 
                                                                            at android.app.ActivityThread.-wrap12(ActivityThread.java) 
                                                                            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477) 
                                                                            at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                            at android.os.Looper.loop(Looper.java:154) 
                                                                            at android.app.ActivityThread.main(ActivityThread.java:6119) 
                                                                            at java.lang.reflect.Method.invoke(Native Method) 
                                                                            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
                                                                            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 

这是我的代码：

class StopwatchActivity : AppCompatActivity() {

lateinit var textView: TextView

lateinit var start: Button

lateinit var pause: Button
lateinit var reset: Button
lateinit var lap: Button

var MillisecondTime: Long = 0
var StartTime:Long = 0
var TimeBuff:Long = 0
var UpdateTime = 0L

lateinit var handler: Handler

var Seconds: Int = 0
var Minutes:Int = 0
var MilliSeconds:Int = 0

lateinit var listView: ListView

var ListElements = arrayOf<String>()

lateinit var ListElementsArrayList: MutableList<String>

lateinit var adapter: ArrayAdapter<String>


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


    textView = textView as TextView
    start = button as Button
    pause = button2 as Button
    reset = button3 as Button
    lap = button4 as Button
    listView = listview1 as ListView

    handler = Handler()

    ListElementsArrayList = ArrayList(Arrays.asList(*ListElements))

    adapter = ArrayAdapter(this,
            android.R.layout.simple_list_item_1,
            ListElementsArrayList
    )

    listView.adapter = adapter

    start.setOnClickListener {
        StartTime = SystemClock.uptimeMillis()
        handler.postDelayed(runnable, 0)

        reset.setEnabled(false)
    }

    pause.setOnClickListener(View.OnClickListener {
        TimeBuff += MillisecondTime

        handler.removeCallbacks(runnable)

        reset.setEnabled(true)
    })

    reset.setOnClickListener(View.OnClickListener {
        MillisecondTime = 0L
        StartTime = 0L
        TimeBuff = 0L
        UpdateTime = 0L
        Seconds = 0
        Minutes = 0
        MilliSeconds = 0

        textView.text = "00:00:00"

        ListElementsArrayList.clear()

        adapter.notifyDataSetChanged()
    })

    lap.setOnClickListener(View.OnClickListener {
        ListElementsArrayList.add(textView.text.toString())

        adapter.notifyDataSetChanged()
    })

}

var runnable: Runnable = object : Runnable {

    override fun run() {

        MillisecondTime = SystemClock.uptimeMillis() - StartTime

        UpdateTime = TimeBuff + MillisecondTime

        Seconds = (UpdateTime / 1000).toInt()

        Minutes = Seconds / 60

        Seconds = Seconds % 60

        MilliSeconds = (UpdateTime % 1000).toInt()

        textView.text = ("" + Minutes + ":"
                + String.format("%02d", Seconds) + ":"
                + String.format("%03d", MilliSeconds))

        handler.postDelayed(this, 0)
    }

}
}

我试图确切地看到我的textView出现了什么问题，但我没有看到任何可能导致问题的内容。我把它交给私人，初始化和所有这些，但我不知道

非常感谢任何帮助：）

由于

XML：

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.reecreate.woderator2.Controller.StopwatchActivity"
    tools:layout_editor_absoluteX="0dp"
    tools:layout_editor_absoluteY="25dp">

    <TextView
        android:text="00:00:00"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textView"
        android:textSize="50dp"
        android:textStyle="bold"
        android:textColor="#009688"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" />

    <Button
        android:text="Start"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="41dp"
        android:id="@+id/button" />

    <Button
        android:text="Pause"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/button2"
        android:layout_alignBaseline="@+id/button"
        android:layout_alignBottom="@+id/button"
        android:layout_centerHorizontal="true" />

    <Button
        android:text="Reset"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@+id/button2"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:id="@+id/button3" />

    <Button
        android:text="Save Lap"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp"
        android:id="@+id/button4"
        android:layout_below="@+id/button"
        android:layout_centerHorizontal="true" />

    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@+id/button4"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="12dp"
        android:id="@+id/listview1"/>

</RelativeLayout>

Answer 1

您似乎正在使用Kotlin Android Extensions。在这种情况下，您不必为视图创建lateinit var，您只需在XML文件中引用它们的ID即可。

所以不要这样：

class StopwatchActivity : AppCompatActivity() {

    lateinit var textView: TextView

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

        textView = textView as TextView

        textView.text = "00:00:00"
    }

}

这样做：

class StopwatchActivity : AppCompatActivity() {

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

        textView.text = "00:00:00"
    }

}

与你所有其他观点相同。

有关Kotlin Android Extensions以外的选项，请参阅this discussion。