java.awt.Container#getBackground ( )源码实例Demo

@Override
protected void installDefaults( JRootPane c ) {
	super.installDefaults( c );

	// Update background color of JFrame or JDialog parent to avoid bad border
	// on HiDPI screens when switching from light to dark Laf.
	// The background of JFrame is initialized in JFrame.frameInit() and
	// the background of JDialog in JDialog.dialogInit(),
	// but it was not updated when switching Laf.
	Container parent = c.getParent();
	if( parent instanceof JFrame || parent instanceof JDialog ) {
		Color background = parent.getBackground();
		if( background == null || background instanceof UIResource )
			parent.setBackground( UIManager.getColor( "control" ) );
	}

	// enable dark window appearance on macOS when running in JetBrains Runtime
	if( SystemInfo.IS_JETBRAINS_JVM && SystemInfo.IS_MAC_OS_10_14_MOJAVE ) {
		LookAndFeel laf = UIManager.getLookAndFeel();
		boolean isDark = laf instanceof FlatLaf && ((FlatLaf)laf).isDark();
		c.putClientProperty( "jetbrains.awt.windowDarkAppearance", isDark );
	}
}
 

/**
 * Gets the background color of the first opaque parent.
 */
public static Color getParentBackground( JComponent c ) {
	Container parent = findOpaqueParent( c );
	return (parent != null)
		? parent.getBackground()
		: UIManager.getColor( "Panel.background" ); // fallback, probably never used
}
 

/**
 * Resolves background color. Must be called after getColoring(), satisfied in updateColors.
 * @return 
 */
private Color resolveBackColor(boolean fallback) {
    AttributeSet attr = specificAttrs;
    Color x = (Color)attr.getAttribute(StyleConstants.ColorConstants.Background);
    if (x == null) {
        Container c = getParent();
        if (c != null) {
            x = c.getBackground();
        } else if (fallback) {
            // fallback in case of inherited color and uninitialized parent
            return getColoring().getBackColor();
        }
    }
    return x;
}