小编oli*_*s98的帖子

我最近遇到一个错误，导致任何 Jetpack Compose 预览无法显示，如下所示：

Failed to instantiate one or more classes
The following classes could not be instantiated:
     -androidx.compose.ui.tooling.ComposeViewAdapter(Open Class, Show Exception, Clear Cache)

if this is an unexpected error you can also try to build the project, then manually refresh the layout

java.lang.NoClassDefFoundError: Could not initialize class androidx.customview.poolingcontainer.PoolingContainer
    at androidx.compose.ui.platform.ViewCompositionStrategy$DisposeOnDetachedFromWindowIfNotInPoolingContainer.installFor(ViewCompositionStrategy.android.kt:97)
    at androidx.compose.ui.platform.AbstractComposeView.<init>(ComposeView.android.kt:123)
    at androidx.compose.ui.platform.ComposeView.<init>(ComposeView.android.kt:392)
    at androidx.compose.ui.platform.ComposeView.<init>(ComposeView.android.kt:388)
    at androidx.compose.ui.tooling.ComposeViewAdapter.<init>(ComposeViewAdapter.kt:131)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
    at org.jetbrains.android.uipreview.ViewLoader.createNewInstance(ViewLoader.java:339)
    at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:176)
    at org.jetbrains.android.uipreview.ViewLoader.loadView(ViewLoader.java:136)
    at com.android.tools.idea.rendering.LayoutlibCallbackImpl.loadView(LayoutlibCallbackImpl.java:301)
    at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:417)
    at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:428) …

当键盘的 KeyboardType 设置为 KeyboardType.Number 时，我当前无法捕获用户输入到文本字段中。

如果键盘设置为 KeyboardType.Text，则文本字段会按预期更新，但是当设置为 KeyboardType.Number 时，文本字段将无法更新。

为什么是这样？以及如何更改我的代码，以便在单击文本字段时显示数字键盘，并且在按下数字时在文本字段中更新相关数字。

以下代码不会更新文本字段（当设置为 KeyboardType.Number 时）...

@Composable
fun MyNumberField() {

    var text = remember { mutableStateOf("")}

    val change : (String) -> Unit = { it ->
        value.value = it
    }

    TextField(
        value = text.value,
        modifier = Modifier.fillMaxWidth(),
        keyboardOptions = KeyboardOptions.Default.copy(keyboardType = KeyboardType.Number),
        onValueChange = change
    )

}

以下代码确实更新了文本字段（当设置为 KeyboardType.Text 时）...

@Composable
fun MyNumberField() {

    var text = remember { mutableStateOf("")}

    val change : (String) -> Unit = { it ->
        text.value = it …