java.lang.ClassCastException 尝试向 textview 添加约束时

Question

我正在以编程方式创建约束布局并向其添加文本视图，但是当我尝试添加约束时它引发了 java.lang.ClassCastException 异常。这是我的代码：

var textlayoutbottom = ConstraintLayout(this)
                    textlayout.addView(textlayoutbottom)

                    var typelabel = TextView(this)
                    textlayoutbottom.addView(typelabel)

                    textlayoutbottom.layoutParams = ConstraintLayout.LayoutParams(ConstraintLayout.LayoutParams.MATCH_PARENT, ConstraintLayout.LayoutParams.MATCH_PARENT)

                    typelabel.text = getAnimeType(anime.type)

                    var params = typelabel.layoutParams as ConstraintLayout.LayoutParams
                    params.leftToLeft = textlayoutbottom.id
                    params.bottomToBottom = textlayoutbottom.id
                    typelabel.requestLayout()

但是应用程序崩溃了，甚至没有显示错误行。

这是我的日志：

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.my.package, PID: 5234
    java.lang.ClassCastException: androidx.constraintlayout.widget.ConstraintLayout$LayoutParams cannot be cast to android.widget.LinearLayout$LayoutParams
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:731)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:640)
        at android.view.View.measure(View.java:19857)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
        at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1117)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:642)
        at android.view.View.measure(View.java:19857)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:758)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:640)
        at android.view.View.measure(View.java:19857)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:758)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:640)
        at android.view.View.measure(View.java:19857)
        at android.widget.ScrollView.measureChildWithMargins(ScrollView.java:1293)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.widget.ScrollView.onMeasure(ScrollView.java:340)
        at android.view.View.measure(View.java:19857)
        at androidx.constraintlayout.widget.ConstraintLayout$Measurer.measure(ConstraintLayout.java:792)
        at androidx.constraintlayout.solver.widgets.ConstraintWidgetContainer.measure(ConstraintWidgetContainer.java:583)
        at androidx.constraintlayout.solver.widgets.ConstraintWidgetContainer.layout(ConstraintWidgetContainer.java:682)
        at androidx.constraintlayout.solver.widgets.analyzer.BasicMeasure.solveLinearSystem(BasicMeasure.java:159)
        at androidx.constraintlayout.solver.widgets.analyzer.BasicMeasure.solverMeasure(BasicMeasure.java:290)
        at androidx.constraintlayout.solver.widgets.ConstraintWidgetContainer.measure(ConstraintWidgetContainer.java:119)
        at androidx.constraintlayout.widget.ConstraintLayout.resolveSystem(ConstraintLayout.java:1578)
        at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1690)
        at android.view.View.measure(View.java:19857)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at androidx.appcompat.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:146)
        at android.view.View.measure(View.java:19857)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:758)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:640)
        at android.view.View.measure(View.java:19857)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.view.View.measure(View.java:19857)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:758)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:640)
        at android.view.View.measure(View.java:19857)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at com.android.internal.policy.DecorView.onMeasure(DecorView.java:689)
        at android.view.View.measure(View.java:19857)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2275)
E/AndroidRuntime:     at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1366)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1619)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1254)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6337)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:874)
        at android.view.Choreographer.doCallbacks(Choreographer.java:686)
        at android.view.Choreographer.doFrame(Choreographer.java:621)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:860)
        at android.os.Handler.handleCallback(Handler.java:751)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        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)

有什么想法吗？

Answer 1

您好，您正在将 ConstraintLayout.LayoutParams 设置为 ConstraintLayout 本身，尝试将其设置为 TextView，对于 textlayoutbottom 使用 LinearLayout.LayoutParams

textlayoutbottom.layoutParams = LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT) //for constraint layout
typeLabel.layoutParams = ConstraintLayout.LayoutParams(ConstraintLayout.LayoutParams.MATCH_PARENT, ConstraintLayout.LayoutParams.MATCH_PARENT)//for typeLabel

java.lang.ClassCastException 尝试向 textview 添加约束时

java.lang.ClassCastException when trying to add constraints to textview

android

exception

constraints

kotlin