Question

我有一个for循环，每次循环都会创建一个cardView，然后它为每个具有不同附加功能的视图使用setOnClickListener，问题是最后一个循环参数被设置为每个创建的卡，这是我的代码：

        for (finalItem1 in finalList1) {
            thePoints.clear()
            theSteps.clear()
            theIcons.clear()
            val step1 =
                "${getString(R.string.from_your_location)} \n ${getString(R.string.move_to)} \n $theStartStation"
            theSteps.add(step1)
            theIcons.add("ic_walk")
            thePoints.add(stationData[theStartStation]?.latitude.toString())
            thePoints.add(stationData[theStartStation]?.longitude.toString())
            val step2 =
                "${getString(R.string.from)} : $theStartStation \n ${getString(R.string.take)} : ${finalItem1.child("transportation_type").value} \n ${finalItem1.child("notes").value} \n ${finalItem1.child("price").value} EGP \n ${getString(R.string.to)} : $theEndStation"
            theSteps.add(step2)
            theIcons.add("ic_bus")
            thePoints.add(stationData[theEndStation]?.latitude.toString())
            thePoints.add(stationData[theEndStation]?.longitude.toString())
            val cardView = CardView(this)
            val cardLinearLayout = LinearLayout(this)
            cardLinearLayout.orientation = LinearLayout.VERTICAL
            val params = RelativeLayout.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.WRAP_CONTENT
            )
            params.setMargins(16, 16, 16, 16)
            cardView.radius = 15f
            cardView.setCardBackgroundColor(Color.parseColor("#64b0e3"))
            cardView.setContentPadding(36, 36, 36, 36)
            cardView.layoutParams = params
            cardView.cardElevation = 30f
            val quote = TextView(this)
            quote.text = "${getString(R.string.from)} $theStartStation \n ${finalItem1.child("notes").value} \n ${finalItem1.child("price").value} EGP"
            cardLinearLayout.addView(quote)
            cardView.addView(cardLinearLayout)
            optionsLayout.addView(cardView)
            cardView.setOnClickListener {
                val tripIntent =
                    Intent(this, NavigationActivity::class.java)
                tripIntent.putStringArrayListExtra("theSteps",
                    theSteps as java.util.ArrayList<String>?
                )
                tripIntent.putStringArrayListExtra("theIcons",
                    theIcons as java.util.ArrayList<String>?
                )
                tripIntent.putStringArrayListExtra("thePoints",
                    thePoints as java.util.ArrayList<String>?
                )
                tripIntent.putExtra("fromLat", fromLocation.latitude)
                tripIntent.putExtra("fromLon", fromLocation.longitude)
                tripIntent.putExtra("toLat", toLocation.latitude)
                tripIntent.putExtra("toLon", toLocation.longitude)
                startActivity(tripIntent)
            }

问题出在这里： val cardView = CardView(this)

因为它为每张卡cardView.setOnClickListener创建了相同的侦听器

Answer 1

每个侦听器实例都引用在循环外部声明的theSteps，theIcons和theIcons对象。您清除这些列表，然后在每个循环迭代中向其中添加项目，因此实际上仅使用上一次迭代中的值。只需在循环中声明这些列表即可。

如何每次在Kotlin中的for循环中创建一个新变量

1 个答案: