活动的昏暗背景 [英] Dim background of an activity

问题描述

我正在尝试将活动显示为背景暗淡的浮动窗口，并且我使用以下代码来实现此目的，该代码取自Google I/O 2016项目:

I am trying to show an activity as a floating window with a dimmed background and I'm using the following code to do that, which is taken from the Google I/O 2016 project:

    protected void setupFloatingWindow(int width, int height, int alpha, float dim) {
    WindowManager.LayoutParams params = getWindow().getAttributes();
    params.width = getResources().getDimensionPixelSize(width);
    params.height = getResources().getDimensionPixelSize(height);
    params.alpha = alpha;
    params.dimAmount = dim;
    params.flags |= WindowManager.LayoutParams.FLAG_DIM_BEHIND;
    getWindow().setAttributes(params);
}

我在super.onCreate和setContentView之前的onCreate中调用此函数，就像在Google I/O示例代码中一样.

I am calling this function in onCreate, before super.onCreate and setContentView , as it is in the Google I/O example code.

这样，它对我不起作用.该活动显示为一个浮动窗口，具有我设置的大小，但是后面的背景是黑色的，并且不像我期望的那样暗淡.我要设置的dimAmount为0.4f.

This way it doesn't work for me. The activity is shown as a floating window, with the size that I am setting, but the background behind is black and not dimmed as I expect it to be. The dimAmount that I am setting is 0.4f.

我错过了什么吗?我应该再添加些东西吗?请帮助

Am I missing something? Should I add something more? Please help

推荐答案

要尝试的两件事:

params.alpha值是一个浮点数，应在0.0到1.0之间，但是您要传递一个int值，因此alpha值将设置为完全不透明或完全透明，而中间没有任何内容.

The params.alpha value is a float that should be between 0.0 and 1.0, but you are passing an int, so the alpha value gets set to fully opaque or fully transparent, nothing in between.

此外，在将活动样式更改为包括以下内容后，我只能在模拟器上运行此功能:

Also, I was only able to get this working on my emulator after changing the activity style to include:

<item name="android:windowIsTranslucent">true</item>

我不知道您正在使用的项目中是否设置了该值.

I don't know if that's set in the project you are working from or not.

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