java Android.widget.RelativeLayout 不能转换为 android.widget.ImageView
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Android.widget.RelativeLayout cannot be cast to android.widget.ImageView
提问by felixd
I'm trying to get the instance of a ImageView defined in an XML layout file:
我正在尝试获取在 XML 布局文件中定义的 ImageView 实例：
<RelativeLayout
android:id="@+id/visual_compass_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/output_container" >
<ImageView
android:id="@+id/visual_compass"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:contentDescription="Compass"
android:scaleType="fitStart"
android:src="@drawable/compass_rose" />
</RelativeLayout>
But I always get that runtime error:
但我总是得到那个运行时错误：
... java.lang.ClassCastException: android.widget.RelativeLayout cannot be
cast to android.widget.ImageView ... at net.example.MainActivity.onCreate
(MainActivity.java:57)
Line "57" is that one:
第“57”行是那一行：
compassView = (ImageView) findViewById(R.id.visual_compass);
I can't figure out why that error ist thrown; I don't see the problem with that piece of code. Does anybody elso know?
我无法弄清楚为什么会抛出该错误；我没有看到那段代码的问题。还有人知道吗？
Thank you, Felix D.
谢谢你，菲利克斯 D。
回答by GrIsHu
Make sure in your code the compassViewis ImageViewvariable only and try to access it as
确保在您的代码中compassView只有ImageView变量并尝试访问它
ImageView compassView = (ImageView) findViewById(R.id.visual_compass);
And if everything is correct then try to clean and Build your project again from the menu Project-> clean.and Proejct-> Build.
如果一切正常，请尝试从菜单Project-> clean.和Proejct-> Build.
