如何为活动根视图设置布局重力

Question

I get the root view (Which in my case happens to be RelativeLayout) using the below code:

final ViewGroup viewGroup = (ViewGroup) ((ViewGroup) this
        .findViewById(android.R.id.content)).getChildAt(0);

Source: Get root view from current activity

Now I want to set the size and the layout gravity of the root view. But I don't know the layout type of its parent

The below code works when the view I want to set it's layout params is inside a LinearLayout.

LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.FILL_PARENT);
params.weight = 1.0f;
params.gravity = Gravity.TOP;

button.setLayoutParams(params);

Source: How to set layout_gravity programmatically?

Answer 1

I believe you need DecorView.LayoutParams .

The root view is added to a DecorView, which is attached to the Activity's Window.

PhoneWindow.java

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Since the DecorView in question isn't accessible to apps in general, you can use FrameLayout.LayoutParams .