安卓:叠加图片(JPG格式)与透明度 [英] Android: Overlay a picture (jpg) with transparency
问题描述
我有一张照片(JPG格式),我想在屏幕上显示。 此外,该图象应该由透明的效果部分覆盖。 透明盖应该是动态的。因此,如每天多画面的显示。 下面的图片来说明我的意思:
I have a picture (jpg) that I want to display on the screen. Additionally the picture should be covered partially by a transparent effect. The transparent cover should be dynamic. So e.g. each day more of the picture is shown. Here a picture to show what I mean:
我有没有灰色封面的图片,并希望添加这个封面,但在不同的步骤。
I have the picture without the gray cover and want to add this cover but in different steps.
有人可以给我一个提示如何做到这一点。
Can someone give me a hint how to do that.
推荐答案
您可以做到这一点简单地用小工具:
You can do this simply with widgets:
的FrameLayout 是一般的机构覆盖视图在另一个之上:
FrameLayout is the general mechanism for overlaying a view on top of another:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView
android:id="@+id/image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/my_image"/>
<View
android:id="@+id/overlay"
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
</FrameLayout>
然后在你的Java code可以动态地设置您的叠加层的透明度:
Then in your Java code you can dynamically set the transparency of your overlay:
View overlay = (View) findViewById(R.id.overlay);
int opacity = 200; // from 0 to 255
overlay.setBackgroundColor(opacity * 0x1000000); // black with a variable alpha
FrameLayout.LayoutParams params =
new FrameLayout.LayoutParams(FrameLayout.LayoutParams.FILL_PARENT, 100);
params.gravity = Gravity.BOTTOM;
overlay.setLayoutParams(params);
overlay.invalidate(); // update the view
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