java.lang.ClassCastException:android.inputmethodservice.KeyboardView无法转换为android.view.ViewGroup [英] java.lang.ClassCastException: android.inputmethodservice.KeyboardView cannot be cast to android.view.ViewGroup

问题描述

尝试在键盘视图内使用其他布局(如在xml文件中)时遇到此错误.我不希望我的键盘布局像普通键盘一样具有行和键，相反，我希望它在任何父布局的顶部两侧都具有两个按钮.另外，我还需要在键盘视图中放置一个布局以包含我的绘图画布.

I am getting this error while trying to use other layouts inside keyboard view as in my xml file. I don't want my keyboard layout to have rows and keys as in normal keyboard instead i want it to have two buttons on either side at the top inside any parent layout. Also I need a layout inside keyboard view to contain my drawing canvas.

我还尝试过这样的布局:

I have also tried to put in a layout like this:

<?xml version="1.0" encoding="utf-8"?>
<android.inputmethodservice.KeyboardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/keyboard"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:keyBackground="@drawable/square_rounded"
    android:background="#ffffff">
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:id="@+id/mainLinearLayout">

    <RelativeLayout
        android:id="@+id/keyboardLayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <Button
            android:layout_width="100dp"
            android:layout_height="50dp"
            android:text="Cancel"
            android:layout_alignParentLeft="true">
        </Button>

        <Button
            android:layout_width="100dp"
            android:layout_height="50dp"
            android:text="Done"
            android:layout_alignParentRight="true">
        </Button>

        <LinearLayout
            android:layout_alignParentTop="true"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

        </LinearLayout>
    </RelativeLayout>
</LinearLayout>
</android.inputmethodservice.KeyboardView>

，然后尝试像这样加载它:

and then tried loading it like:

       kv = (KeyboardView)getLayoutInflater()
        .inflate(R.layout.draw_signature, null);
        kv.setOnKeyboardActionListener(this);
        kv.setPreviewEnabled(false);
        return kv;

任何帮助或教程链接将不胜感激.

Any help or a tutorial link would be appreciated.

推荐答案

您会收到此错误，因为KeyboardView扩展了View，该View不能包含ViewGroup之类的子级.

You get the error because KeyboardView extends View , which cannot contain children like ViewGroup.

要使其正常工作，您需要使用键盘布局创建一个单独的布局文件，然后将其添加到KeyboardView中，如下所示:

In order to make it work you need to create a separate layout file with your keyboard layout and then add it to the KeyboardView like this:

<android.inputmethodservice.KeyboardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/keyboard"
    ...
    android:keyPreviewLayout ="@layout/your_keyboard_layout">

有关如何自定义键盘的完整教程，请参见:

For full tutorial how to customize keyboard : https://code.tutsplus.com/tutorials/create-a-custom-keyboard-on-android--cms-22615

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