英文:
How can I define ImageView with height width and source defined on xml file?
问题
在片段上膨胀视图会导致属性丢失，我如何在 XML 文件中定义具有高度、宽度和源的 ImageView？
我正在使用下面的代码，用于 image_fragment.xml：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ui.main.ImageFragment"
android:orientation="horizontal" >
<ImageView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:contentDescription="测试图片"
tools:src="@drawable/cartoon" />
</LinearLayout>
使用 Kotlin 类来编写片段：
ImageFragment.kt
class ImageFragment : Fragment() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val root = inflater.inflate(R.layout.image_fragment, container, false)
return root
}
}
它什么都没有显示。当我尝试使用调试工具时，我发现 ImageView 的高度和宽度没有定义，所以图片的资源也没有定义。
只有当我使用：
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val root = inflater.inflate(R.layout.image_fragment, container, false)
root.findViewById<ImageView>(R.id.imageView).setImageResource(R.drawable.cartoon)
return root
}
它才显示图片。但是属性仍然丢失。
那么，我应该怎么做才能在 XML 文件中定义属性和图片源呢？
英文:
Inflating view on fragment causing remove the attributes, how can I define ImageView with height width and source defined on xml file?
I am using this code bellow. for image_fragment.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ui.main.ImageFragment"
android:orientation="horizontal" >
<ImageView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:contentDescription="test Image"
tools:src="@drawable/cartoon" />
</LinearLayout>
Using kotlin class for the fragment
ImageFragment.kt
class ImageFragment : Fragment() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val root = inflater.inflate(R.layout.image_fragment, container, false)
return root
}
}
It showing nothin. When I tried debugging tools, I found that, the height and width of the imageview is not defined so is resource of the image.
only if I use
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val root = inflater.inflate(R.layout.image_fragment, container, false)
root.findViewById<ImageView>(R.id.imageView).setImageResource(R.drawable.cartoon)
return root
}
it is showing the image. But attributes are still missing.
So what should do to define attributes and image source in xml file?
答案1
得分: 0
你正在使用 xml 中的 tools，它只显示一个预览。
你必须使用 app:srcCompat：
<ImageView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:contentDescription="测试图片"
app:srcCompat="@drawable/cartoon" />
英文:
you are using tools in xml, it only shows a preview.
you must use app:srcCompat:
<ImageView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:contentDescription="test Image"
app:srcCompat="@drawable/cartoon" />
答案2
得分: 0
正如文档所述
> Android Studio支持在工具命名空间中使用各种XML属性，以实现设计时功能（例如在片段中显示哪个布局）或编译时行为（例如对XML资源应用哪种缩小模式）。构建应用程序时，构建工具会移除这些属性，因此不会影响APK的大小或运行时行为。
因此，tools:src=" @drawable/cartoon" 仅会在设计UI预览中显示，并且会在构建时被移除。
请使用 app:srcCompat=" @drawable/cartoon" 替代 tools:src=" @drawable/cartoon"。
另外，如果要在您的XML文件中使用 app:srcCompat，请确保执行以下操作：
配置您的 build.gradle 文件
android {
defaultConfig {
vectorDrawables {
useSupportLibrary = true
}
}
}
英文:
as document said
> Android Studio supports a variety of XML attributes in the tools
> namespace that enables design-time features (such as which layout to
> show in a fragment) or compile-time behaviors (such as which shrinking
> mode to apply to your XML resources). When you build your app, the
> build tools remove these attributes so there is no effect on your APK
> size or runtime behavior.
so tools:src="@drawable/cartoon" just shows in designing UI preview and it will be removed at build time.
use app:srcCompat="@drawable/cartoon" instead of tools:src="@drawable/cartoon"
also for using app:srcCompat in your XML file, make sure to do the following:
setup your build.gradle file
android {
defaultConfig {
vectorDrawables {
useSupportLibrary = true
}
}
}
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