圓角

從 Android 12 (API 級別 31) 開始,您可以使用 RoundedCornerWindowInsets.getRoundedCorner(int position) 設定圓角的半徑和中心點。只要使用這些 API,應用程式就能避免 UI 元素在圓角螢幕上無法完整顯示的情形。架構還提供 getPrivacyIndicatorBounds() API,可傳回任何可見麥克風和相機指標的邊界矩形。

在應用程式中實作時,這些 API 對於非圓角螢幕的裝置不會產生任何效果。

圓角的半徑和中心點圖片
圖 1:圓角的半徑和中心點

如要實作這項功能,請透過 WindowInsets.getRoundedCorner(int position) 取得相對於應用程式邊界的 RoundedCorner 資訊。如果應用程式未占滿整個螢幕畫面,則 API 在套用圓角時,會讓圓角的中心點以應用程式的視窗邊界為基礎。

以下程式碼片段提供一個簡易範例,說明如何根據 RoundedCorner 的資訊設定檢視區塊的邊界,避免應用程式 UI 無法完整顯示 (在這個例子中為右上方的圓角)。

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 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);