Android 中的重叠视图

在 Android 中是否可能有重叠的视图？我想有一个透明的 png 在前面和另一个视图在后台的 ImageView。

编辑:

这就是我现在所看到的，问题是 imageView 中的图像不是透明的，应该是透明的部分只是黑色的。

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/gallerylayout"
>
<Gallery android:id="@+id/overview"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>


<ImageView android:id="@+id/navigmaske"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:src="@drawable/navigmask"
/>


</RelativeLayout>

编辑:

我让它工作，它是一个主题文件从另一个程序员的团队。 只是换了这个

<item name="android:background">#FF000000</item>

这个

<item name="android:background">#00000000</item>
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Yes, that is possible. The challenge, however, is to do their layout properly. The easiest way to do it would be to have an AbsoluteLayout and then put the two images where you want them to be. You don't need to do anything special for the transparent png except having it added later to the layout.

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A visible gallery changes visibility which is how you get the gallery over other view overlaps. the Home sample app has some good examples of this technique.

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Also, take a look at FrameLayout, that's how the Camera's Gallery application implements the Zoom buttons overlay.

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最佳答案

Android handles transparency across views and drawables (including PNG images) natively, so the scenario you describe (a partially transparent ImageView in front of a Gallery) is certainly possible.

If you're having problems it may be related to either the layout or your image. I've replicated the layout you describe and successfully achieved the effect you're after. Here's the exact layout I used.

<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/gallerylayout"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<Gallery
android:id="@+id/overview"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<ImageView
android:id="@+id/navigmaske"
android:background="#0000"
android:src="@drawable/navigmask"
android:scaleType="fitXY"
android:layout_alignTop="@id/overview"
android:layout_alignBottom="@id/overview"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</RelativeLayout>

Note that I've changed the parent RelativeLayout to a height and width of fill_parent as is generally what you want for a main Activity. Then I've aligned the top and bottom of the ImageView to the top and bottom of the Gallery to ensure it's centered in front of it.

I've also explicitly set the background of the ImageView to be transparent.

As for the image drawable itself, if you put the PNG file somewhere for me to look at I can use it in my project and see if it's responsible.

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If you want to add your custom Overlay screen on Layout, you can create a Custom Linear Layout and get control of drawing and key events. You can my tutorial- Overlay on Android Layout- http://prasanta-paul.blogspot.com/2010/08/overlay-on-android-layout.html

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The simples way arround is to put -40dp margin at the buttom of the top imageview

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Now with Jetpack Compose in android, you should use Box for overlapping views. Example.

Box(modifier = Modifier.fillMaxWidth().fillMaxHeight()){
RecipesList(viewModel.recipes.value)
Snackbar()
}

Here RecipesList and Snackbar are composabes positioned one on top of the other in the composition order

Check out this for Jetpack Compose samples - https://androidlearnersite.wordpress.com/2021/08/03/jetpack-compose-1-0-0-sample-codes/


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