从 Android 12(API 级别 31)开始,您可以使用 RoundedCorner
和 WindowInsets.getRoundedCorner(int
position)
获取设备屏幕圆角的半径和中心点。这些 API 可防止应用的界面元素在带有圆角的屏幕上被截断。框架提供 getPrivacyIndicatorBounds()
API,该 API 会返回任何可见麦克风和摄像头指示标志的有边界矩形。
在您的应用中实现这些 API 时,它们对具有非圆角屏幕的设备没有影响。
![显示带有半径和中心点的圆角的图片](https://developer.android.google.cn/static/guide/topics/ui/images/look-and-feel/rounded-corners-radius.png?authuser=6&hl=el)
如需实现此功能,请相对于应用边界,使用 WindowInsets.getRoundedCorner(int position)
获取 RoundedCorner
信息。如果应用未占据整个屏幕,则 API 会基于应用的窗口边界创建圆角的中心点,从而应用圆角。
以下代码段展示了应用如何通过根据来自 RoundedCorner
的信息设置视图的外边距来避免其界面被截断。在本例中,它是右上角的圆角。
Kotlin
// Get the top-right rounded corner from WindowInsets. val insets = rootWindowInsets val topRight = insets.getRoundedCorner(RoundedCorner.POSITION_TOP_RIGHT) ?: return // Get the location of the close button in window coordinates. val location = IntArray(2) closeButton!!.getLocationInWindow(location) val buttonRightInWindow = location[0] + closeButton.width val buttonTopInWindow = location[1] // Find the point on the quarter circle with a 45-degree angle. val offset = (topRight.radius * Math.sin(Math.toRadians(45.0))).toInt() val topBoundary = topRight.center.y - offset val rightBoundary = topRight.center.x + offset // Check whether the close button exceeds the boundary. if (buttonRightInWindow < rightBoundary << buttonTopInWindow > topBoundary) { return } // Set the margin to avoid truncating. val parentLocation = IntArray(2) getLocationInWindow(parentLocation) val lp = closeButton.layoutParams as FrameLayout.LayoutParams lp.rightMargin = Math.max(buttonRightInWindow - rightBoundary, 0) lp.topMargin = Math.max(topBoundary - buttonTopInWindow, 0) closeButton.layoutParams = lp
Java
// Get the top-right rounded corner from WindowInsets. final WindowInsets insets = getRootWindowInsets(); final RoundedCorner topRight = insets.getRoundedCorner(POSITION_TOP_RIGHT); if (topRight == null) { return; } // Get the location of the close button in window coordinates. int [] location = new int[2]; closeButton.getLocationInWindow(location); final int buttonRightInWindow = location[0] + closeButton.getWidth(); final int buttonTopInWindow = location[1]; // Find the point on the quarter circle with a 45-degree angle. final int offset = (int) (topRight.getRadius() * Math.sin(Math.toRadians(45))); final int topBoundary = topRight.getCenter().y - offset; final int rightBoundary = topRight.getCenter().x + offset; // Check whether the close button exceeds the boundary. if (buttonRightInWindow < rightBoundary << buttonTopInWindow > topBoundary) { return; } // Set the margin to avoid truncating. int [] parentLocation = new int[2]; getLocationInWindow(parentLocation); FrameLayout.LayoutParams lp = (FrameLayout.LayoutParams) closeButton.getLayoutParams(); lp.rightMargin = Math.max(buttonRightInWindow - rightBoundary, 0); lp.topMargin = Math.max(topBoundary - buttonTopInWindow, 0); closeButton.setLayoutParams(lp);
谨慎剪辑
如果界面填满整个显示屏,圆角可能会导致内容裁剪出现问题。例如,图 2 在屏幕的一角显示了图标,并且布局是在系统栏后面绘制的:
![被圆角裁剪的图标](https://developer.android.google.cn/static/develop/ui/views/theming/images/rounded-corners-none.png?authuser=6&hl=el)
您可以通过检查圆角并应用内边距来避免应用内容超出设备的角落,如以下示例所示:
Kotlin
class InsetsLayout(context: Context, attrs: AttributeSet) : FrameLayout(context, attrs) { override fun onLayout(changed: Boolean, left: Int, top: Int, right: Int, bottom: Int) { val insets = rootWindowInsets if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S && insets != null) { applyRoundedCornerPadding(insets) } super.onLayout(changed, left, top, right, bottom) } @RequiresApi(Build.VERSION_CODES.S) private fun applyRoundedCornerPadding(insets: WindowInsets) { val topLeft = insets.getRoundedCorner(RoundedCorner.POSITION_TOP_LEFT) val topRight = insets.getRoundedCorner(RoundedCorner.POSITION_TOP_RIGHT) val bottomLeft = insets.getRoundedCorner(RoundedCorner.POSITION_BOTTOM_LEFT) val bottomRight = insets.getRoundedCorner(RoundedCorner.POSITION_BOTTOM_RIGHT) val leftRadius = max(topLeft?.radius ?: 0, bottomLeft?.radius ?: 0) val topRadius = max(topLeft?.radius ?: 0, topRight?.radius ?: 0) val rightRadius = max(topRight?.radius ?: 0, bottomRight?.radius ?: 0) val bottomRadius = max(bottomLeft?.radius ?: 0, bottomRight?.radius ?: 0) val windowManager = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager val windowBounds = windowManager.currentWindowMetrics.bounds val safeArea = Rect( windowBounds.left + leftRadius, windowBounds.top + topRadius, windowBounds.right - rightRadius, windowBounds.bottom - bottomRadius ) val location = intArrayOf(0, 0) getLocationInWindow(location) val leftMargin = location[0] - windowBounds.left val topMargin = location[1] - windowBounds.top val rightMargin = windowBounds.right - right - location[0] val bottomMargin = windowBounds.bottom - bottom - location[1] val layoutBounds = Rect( location[0] + paddingLeft, location[1] + paddingTop, location[0] + width - paddingRight, location[1] + height - paddingBottom ) if (layoutBounds != safeArea && layoutBounds.contains(safeArea)) { setPadding( calculatePadding(leftRadius, leftMargin, paddingLeft), calculatePadding(topRadius, topMargin, paddingTop), calculatePadding(rightRadius, rightMargin, paddingRight), calculatePadding(bottomRadius, bottomMargin, paddingBottom) ) } } private fun calculatePadding(radius1: Int?, radius2: Int?, margin: Int, padding: Int): Int = (max(radius1 ?: 0, radius2 ?: 0) - margin - padding).coerceAtLeast(0) }
Java
public class InsetsLayout extends FrameLayout { public InsetsLayout(@NonNull Context context) { super(context); } public InsetsLayout(@NonNull Context context, @Nullable AttributeSet attrs) { super(context, attrs); } @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { WindowInsets insets = getRootWindowInsets(); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S && insets != null) { applyRoundedCornerPadding(insets); } super.onLayout(changed, left, top, right, bottom); } @RequiresApi(Build.VERSION_CODES.S) private void applyRoundedCornerPadding(WindowInsets insets) { RoundedCorner topLeft = insets.getRoundedCorner(RoundedCorner.POSITION_TOP_LEFT); RoundedCorner topRight = insets.getRoundedCorner(RoundedCorner.POSITION_TOP_RIGHT); RoundedCorner bottomLeft = insets.getRoundedCorner(RoundedCorner.POSITION_BOTTOM_LEFT); RoundedCorner bottomRight = insets.getRoundedCorner(RoundedCorner.POSITION_BOTTOM_RIGHT); int radiusTopLeft = 0; int radiusTopRight = 0; int radiusBottomLeft = 0; int radiusBottomRight = 0; if (topLeft != null) radiusTopLeft = topLeft.getRadius(); if (topRight != null) radiusTopRight = topRight.getRadius(); if (bottomLeft != null) radiusBottomLeft = bottomLeft.getRadius(); if (bottomRight != null) radiusBottomRight = bottomRight.getRadius(); int leftRadius = Math.max(radiusTopLeft, radiusBottomLeft); int topRadius = Math.max(radiusTopLeft, radiusTopRight); int rightRadius = Math.max(radiusTopRight, radiusBottomRight); int bottomRadius = Math.max(radiusBottomLeft, radiusBottomRight); WindowManager windowManager = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE); Rect windowBounds = windowManager.getCurrentWindowMetrics().getBounds(); Rect safeArea = new Rect( windowBounds.left + leftRadius, windowBounds.top + topRadius, windowBounds.right - rightRadius, windowBounds.bottom - bottomRadius ); int[] location = {0, 0}; getLocationInWindow(location); int leftMargin = location[0] - windowBounds.left; int topMargin = location[1] - windowBounds.top; int rightMargin = windowBounds.right - getRight() - location[0]; int bottomMargin = windowBounds.bottom - getBottom() - location[1]; Rect layoutBounds = new Rect( location[0] + getPaddingLeft(), location[1] + getPaddingTop(), location[0] + getWidth() - getPaddingRight(), location[1] + getHeight() - getPaddingBottom() ); if (!layoutBounds.equals(safeArea) && layoutBounds.contains(safeArea)) { setPadding( calculatePadding(radiusTopLeft, radiusBottomLeft, leftMargin, getPaddingLeft()), calculatePadding(radiusTopLeft, radiusTopRight, topMargin, getPaddingTop()), calculatePadding(radiusTopRight, radiusBottomRight, rightMargin, getPaddingRight()), calculatePadding(radiusBottomLeft, radiusBottomRight, bottomMargin, getPaddingBottom()) ); } } private int calculatePadding(int radius1, int radius2, int margin, int padding) { return Math.max(Math.max(radius1, radius2) - margin - padding, 0); } }
此布局可确定界面是否扩展到圆角区域并在其周围添加内边距。图 3 启用了“Show layout bounds”开发者选项,以更清楚地显示应用的内边距:
![已应用内边距的图标,可使其远离角落。](https://developer.android.google.cn/static/develop/ui/views/theming/images/rounded-corners-both.png?authuser=6&hl=el)
为了确定这一点,此布局将计算两个矩形:safeArea
是圆角半径范围内的区域,layoutBounds
是布局的大小减去任何内边距。如果 layoutArea
完全包含 safeArea
,布局的子级可能会被裁剪。在这种情况下,请添加内边距,以确保布局保留在 safeArea
内。
通过检查 layoutBounds
是否完全封装 safeArea
,您可以避免在布局未扩展到屏幕的边缘时添加内边距。图 4 显示了未在导航栏后面绘制的布局。在这种情况下,布局不会向下延伸到圆角内,因为它们适合导航栏占据的区域内。不需要内边距。
![一种无法在系统栏和导航栏后面绘制的布局。](https://developer.android.google.cn/static/develop/ui/views/theming/images/rounded-corners-neither.png?authuser=6&hl=el)