如何隐藏键盘。系统服务在 onCreate() 之前对 Activity 不可用

Question

onCreate() 之前的 Activity 无法使用系统服务

我有对话框 class MyPersonalDialog(mContext: Context)，这个对话框包含 EditText。我通过在其中解析上下文来启动 class MyPersonalDialog。 val myPersonalDialog = MyPersonalDialog(这个)

然后我打电话给我 myPersonalDialog.showMyDialog

这个class:

class MyPersonalDialog(mContext: Context){

    fun showMyDialog(){
    val builder = AlertDialog.Builder(context)
    val layoutInflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
    val view = layoutInflater.inflate(R.layout.dialog_edit_list_title, null)
    view.renameListTitle.requestFocus()
    val inputHelper = InputHelper(context)
    inputHelper.showDialogKeyboard()
    builder.setView(view)
    builder.setNegativeButton(R.string.cancel, { dialogInterface: DialogInterface, i: Int ->
        inputHelper.hideKeyboard(activity, view)
    })
    //some other code goes next
}

}

当用户按下 NegativeButton 按钮时，隐藏键盘开始工作

class InputHelper(val context: Context){
fun hideKeyboard(activity: Activity, view: View) {
        val inputManager = activity.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
        inputManager.hideSoftInputFromWindow(view.windowToken, InputMethodManager.HIDE_NOT_ALWAYS)
}
}

但是出现这个错误： java.lang.IllegalStateException: onCreate()

之前的 Activity 无法使用系统服务

我该如何解决这个问题？我不明白为什么会出现这个错误，因为 MyPersonalDialog class 是在 onCreate

之后启动的

找到解决方案：

class InputHelper(val context: Context){
fun showDialogKeyboard() {
    val inputMethodManager = context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
    inputMethodManager.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0)
}

fun hideKeyboard(view: View) {
        val inputManager = context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
        inputManager.hideSoftInputFromWindow(view.getWindowToken(),0);
}}

Answer 1

将此添加到清单中的 Activity -

android:windowSoftInputMode="stateHiddenAlways"

Answer 2

 fun hideKeyboard(activity: Activity) {
        val imm = activity.getSystemService(Activity.INPUT_METHOD_SERVICE) as InputMethodManager
        //Find the currently focused view, so we can grab the correct window token from it.
        var view = activity.currentFocus
        //If no view currently has focus, create a new one, just so we can grab a window token from it
        if (view == null) {
            view = View(activity)
        }
        imm.hideSoftInputFromWindow(view.windowToken, 0)
    }

Answer 3

recyclerViewOfLists = RecyclerViewOfLists(cursor, this, MainActivity())

您不能仅通过调用构造函数来实例化活动 - 例如在这里您正在实例化一个新的 MainActivity。此类活动不会针对您需要 activity 的任何内容进行初始化，例如访问系统服务或以其他方式用作 Context.

不创建新实例，而是使用 this 传递对现有实例的引用，例如

recyclerViewOfLists = RecyclerViewOfLists(cursor, this, this)

Answer 4

尝试更换 fun hideKeyboard(activity: Activity, view: View) { val inputManager = context.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager inputManager.hideSoftInputFromWindow(view.windowToken, InputMethodManager.HIDE_NOT_ALWAYS) } } 在 InputHelper

如何隐藏键盘。系统服务在 onCreate() 之前对 Activity 不可用

How to hide keyboard. System services not available to Activities before onCreate()

android

android-softkeyboard

kotlin