Xamarin C#：试图水平居中按钮会导致它离开屏幕

Posted 2023-03-29

【中文标题】Xamarin C#：试图水平居中按钮会导致它离开屏幕

【英文标题】：Xamarin C#: Trying to center button horizontally causes it to go off screen

【发布时间】：2018-06-12 17:19:54

【问题描述】：

基本上我正在尝试使用屏幕百分比放置按钮。百分比大小和百分比位置。按钮放置在 X: 0.5f 和 Y: 0.0f，这意味着它应该位于屏幕顶部的中心。

Button button = new Button(Application.Context);
int height = Convert.ToInt32(Application.Context.Resources.DisplayMetrics.HeightPixels * heightPercent);
int width = Convert.ToInt32(Application.Context.Resources.DisplayMetrics.WidthPixels * widthPercent);

RelativeLayout.LayoutParams params1 = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WrapContent, RelativeLayout.LayoutParams.WrapContent)

    LeftMargin = Convert.ToInt32(Application.Context.Resources.DisplayMetrics.WidthPixels * xPercent - (width / 2)),
    TopMargin = Convert.ToInt32(Application.Context.Resources.DisplayMetrics.HeightPixels * yPercent),
    BottomMargin = Convert.ToInt32(Application.Context.Resources.DisplayMetrics.HeightPixels * yPercent) + height,
    RightMargin = Convert.ToInt32(Application.Context.Resources.DisplayMetrics.WidthPixels * xPercent + (width / 2)),
    Width = width,
    Height = height
;


button.Tag = buttonID;
button.LayoutParameters = params1;

上面的代码会导致按钮离开屏幕，尽管这没有任何意义。如果我将边距更改为此；

LeftMargin = Convert.ToInt32(Application.Context.Resources.DisplayMetrics.WidthPixels * xPercent),
TopMargin = Convert.ToInt32(Application.Context.Resources.DisplayMetrics.HeightPixels * yPercent),
BottomMargin = Convert.ToInt32(Application.Context.Resources.DisplayMetrics.HeightPixels * yPercent) + height,
RightMargin = Convert.ToInt32(Application.Context.Resources.DisplayMetrics.WidthPixels * xPercent) + width,

按钮将出现在屏幕上，但会稍微向右偏移。我试图将它向左移动一半大小，但我不知道为什么布局会出错。有什么提示吗？

按钮如何添加到布局中：

int MaxWidth = Resources.DisplayMetrics.WidthPixels;
int MaxHeight = Resources.DisplayMetrics.HeightPixels;

base.OnCreate(bundle);
RelativeLayout layout = new RelativeLayout(this);

layout.SetMinimumHeight(MaxHeight);
layout.SetMinimumWidth(MaxWidth);

<BUTTON GETS CREATED HERE>

layout.AddView(button);
SetContentView(layout);

【问题讨论】：

您在哪里将Button 添加到您的布局中？你的Button 的父视图是什么？请发布您的代码。

@YorkShen-MSFT 我添加了用于添加按钮的代码。

【参考方案1】：

Xamarin C#：试图水平居中按钮会导致它离开屏幕

您可以使用LayoutRules.CenterHorizontal 来实现此功能，例如：

RelativeLayout layout = new RelativeLayout(this);
Button button = new Button(this);
button.Text = "Center Button";

RelativeLayout.LayoutParams parametros = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WrapContent, RelativeLayout.LayoutParams.WrapContent);
parametros.AddRule(LayoutRules.CenterHorizontal);
layout.AddView(button, parametros);

SetContentView(layout);

Effect.