当切换到橡皮工具时设置橡皮工具的宽度。示例代码如下：

mUiExtensionsManager.registerToolHandlerChangedListener(new UIExtensionsManager.ToolHandlerChangedListener() {  
    @Override  
    public void onToolHandlerChanged(ToolHandler oldToolHandler, ToolHandler newToolHandler) {  
        if (newToolHandler != null) {  
            String type = newToolHandler.getType();  
            if (ToolHandler.TH_TYPE_ERASER.equals(type)) {  
                EraserToolHandler eraserToolHandler = (EraserToolHandler) newToolHandler;  
                eraserToolHandler.setThickness(36f);  
            }  
        }  
    }  
});